RADON

Editor's Note: This material is not listed in the Emergency Response Guidebook. Based on the material's physical and chemical properties, toxicity, or chemical group, a guide has been assigned. For additional technical information, contact one of the emergency response telephone numbers listed under Public Safety Measures.

MOLECULAR FORMULA

ERG GUIDE NUMBER

163-RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)

SYNONYM REFERENCE

(Budavari, 2000;(HSDB , 2002; Lewis, 2000)

USES/FORMS/SOURCES

USES

Radon is used to start and affect chemical reactions, in surface reaction studies as a surface label, in the determination of thorium and radium, in filtration studies, and as a source of neutrons in combination with beryllium or other light filters. Radon is also used as a therapeutic catalyst for antineoplastic radiation (Budavari, 2000). This noble gas is also used as a tracer to detect leaks, in measurement of flow-rates, radiography, chemical research, and as a cancer treatment (Lewis, 2001).
In some countries, "radon mines," caves with high radon concentrations, and radon "spas" are being used as health treatments for ailments such as arthritis, asthma, allergies, diabetes, hypertension, ulcers, and cancer (ATSDR, 1990).
Radon is also being used as part of new earthquake prediction technology. This technology uses radon emanation from soil and groundwater concentrations as crustal activity indicators (ATSDR, 1990).

FORMS

Radon is a colorless, odorless, inert gas. All 21 isotopes of radon are radioactive, with mass numbers ranging from 202 to 224. The common isotopes are Rn-222, Rn-220, and Rn-219, with half-lives of 3.82 days, 55.3 seconds, and 4.0 seconds, respectively ((ATSDR, 2000)) Patnaik, 1992).
Radon is an alpha-emitter and a member of the decay chain of uranium 238. Known artificial radioactive isotopes include radon 200-221 and 223-226 (Budavari, 2000).
With a half-life of 3.823 days, radon-222 is the longest-lived known radon isotope (Budavari, 2000).

SOURCES

Radon is derived from the radioactive decay of uranium to radium then radon. Uranium exists in soil and rocks in small amounts. Approximately 1 gram of radium exists for each 6-inch-deep square mile of soil. Radon is released from this radium into the atmosphere (ATSDR, 1990; (ATSDR, 2000)). At normal temperature and pressure, 1 gram of radium produces approximately 0.0001 mL of radon per day (HSDB , 2002).
Radon is produced by alpha-disintegration of radium and its isotopes (Patnaik, 1992). "Radon is [also] obtained by bubbling air through a radon salt solution and collecting the gas plus air" (Lewis, 2001).
Both uranium-238 and radium-226 occur naturally in most soils and rock (Berger, 1990).
The radon decay product leaves the soil or rock as it is formed and becomes ubiquitous in the environment (Berger, 1990). Higher radon concentrations are produced in areas with richer sources of the precursor radionuclides, especially when ventilation is poor (Berger, 1990).
Radon levels are higher in areas with uranium and thorium ore deposits and granite formations. Natural uranium exists in these locations in high concentrations. In the United States, eastern Pennsylvania and parts of New York and New Jersey have high radon concentrations because of the presence of granite formations (ATSDR, 1990).
Other natural sources of radon are plants, groundwater, and oceans (WHO, 1983).
Other radon sources include natural construction materials such as alum slate and by-products from the treatment and production of such materials (ILO , 1998).
Radon and its daughters can be present in indoor air in homes from such sources as underlying soil, various building materials, ground and well water, and contaminated natural gas (Berger, 1990) NTP, 2001; (WHO, 1983).
Certain building materials, such as aerated concrete with alum shale and phospho-gypsum from sedimentary ores, have a higher radon content. Excluding these, the average radium radiation concentration in building materials is about 100 becquerels/kilogram (WHO, 1983).
Radon levels in homes can vary widely, and are largely dependent on such factors as ventilation and air pressure in the building. The average home air level is about 1 picocurie/liter (pCi/L), with some homes having concentrations as high as 10 to 100 pCi/L (Berger, 1990). An estimated six million homes in the United States have radon levels greater than 4 pCi/L ((ATSDR, 2000)).

Homes in areas with significant deposits of granite, uranium, shale, and phosphate are more likely to have elevated levels of radon ((ATSDR, 2000)).

SYNONYM EXPLANATION

RELATED COMPOUNDS (Berger, 1990; ATSDR, 1990)

RADON DAUGHTERS
RADON PROGENY
RADON DEGRADATION PRODUCTS
POLONIUM-218
LEAD-214
BISMUTH-214
POLONIUM-214
POLONIUM-210

RELATED COMPOUNDS (Berger, 1990; ATSDR, 1990)RADON DAUGHTERSRADON PROGENYRADON DEGRADATION PRODUCTSPOLONIUM-218LEAD-214BISMUTH-214POLONIUM-214POLONIUM-210

RADON DAUGHTERS
RADON PROGENY
RADON DEGRADATION PRODUCTS
POLONIUM-218
LEAD-214
BISMUTH-214
POLONIUM-214
POLONIUM-210

Radon daughters are short-lived decay products from radon. Some of these may be as hazardous to health as radon (Samet, 1991).

Two isotopes, radon-220 and radon-222 (CAS 14859-67-7) occur most often (ILO , 1998). With a half-life of 3.823 days, radon-222 is the longest-lived known radon isotope (Budavari, 2000) and is considered most frequently in radon-induced health effects (ATSDR, 1990); thus, in some literature, discussions of radon may actually be referring to radon-222 (ATSDR, 1990).

-CLINICAL EFFECTS

GENERAL CLINICAL EFFECTS

Radon is a naturally occurring radioactive gas. The main concern after exposure to radon and its daughters (decay products) exposure concern is the development of lung cancer. An increased risk of lung cancer has been clearly documented in uranium and certain other miners exposed to radon and its daughters, as well as in experimental animals.

Radon and its daughters are absorbed into the lungs by inhalation after becoming attached to microscopic particles of environmental airborne dust. Inhaled dust particles with attached radon daughters are distributed in the lungs, where they may stick to the moist bronchial epithelial lining.
Mucociliary clearance may not be rapid enough to prevent ionizing radiation (alpha particles) released from the decay of the radon daughters, polonium-218 and polonium-214, from affecting several types of pulmonary cells and eventually leading to cancerous transformation.
Uranium ore has particularly high concentrations of radium. Other types of ore (zinc, lead, fluorospar, tin, niobium, and iron) containing uranium and radium can also release radon and its daughters. When ventilation is not adequate, miners can be at risk for an increased incidence of lung tumors. Cutting uranium metal may release dust containing radon and its daughters.

Radon exposure is thought to be an important environmental cause of death. The US EPA and the National Cancer Institute estimate that there are 15,000 deaths annually in the US from radon induced lung cancer. Of the 164,100 cases of lung cancer diagnosed each year, approximately 14% are attributable to radon exposure. After cigarette smoking, indoor radon is the second leading cause of lung cancer.

Smokers are at greater risk for the development of lung cancer. The risk of lung cancer in cigarette smokers is 10 times that of non-smokers.
Lifetime exposure to the EPA recommended guideline of 4 pCi/L is estimated to pose a 1-5% risk for developing lung cancer depending if a person is a nonsmoker or smoker.

Radon is odorless, colorless, tasteless, and not irritating; there is no way to detect its presence other than sampling and laboratory measurement.

The dose of ionizing radiation received by the bronchial epithelium in the general population from radon is far in excess of the dose received by any other organs from natural background radiation.

POTENTIAL HEALTH HAZARDS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Radiation presents minimal risk to transport workers, emergency response personnel and the public during transportation accidents. Packaging durability increases as potential hazard of radioactive content increases.
Undamaged packages are safe. Contents of damaged packages may cause higher external radiation exposure, or both external and internal radiation exposure if contents are released.
Type A packages (cartons, boxes, drums, articles, etc.) identified as "Type A" by marking on packages or by shipping papers contain non-life endangering amounts. Partial releases might be expected if "Type A" packages are damaged in moderately severe accidents.
Type B packages, and the rarely occurring Type C packages, (large and small, usually metal) contain the most hazardous amounts. They can be identified by package markings or by shipping papers. Life threatening conditions may exist only if contents are released or package shielding fails. Because of design, evaluation, and testing of packages, these conditions would be expected only for accidents of utmost severity.
The rarely occurring "Special Arrangement" shipments may be of Type A, Type B or Type C packages. Package type will be marked on packages, and shipment details will be on shipping papers.
Radioactive White-I labels indicate radiation levels outside single, isolated, undamaged packages are very low (less than 0.005 mSv/h (0.5 mrem/h)).
Radioactive Yellow-II and Yellow-III labeled packages have higher radiation levels. The transport index (TI) on the label identifies the maximum radiation level in mrem/h one meter from a single, isolated, undamaged package.
Some radioactive materials cannot be detected by commonly available instruments.
Water from cargo fire control may cause pollution.

ACUTE CLINICAL EFFECTS

In humans, acute radon exposure produces no clinical effects.

CHRONIC CLINICAL EFFECTS

Segmental or sector-shaped radiation cataracts have been reported in patients previously treated with radon gold seed implants for squamous or basal cell carcinomas on or near the eyelids. The incidence of such cataracts was progressive from 6 to 11 years after treatment (Britten et al, 1966).

A false aneurysm of the vertebral artery at the level of the axis vertebra developed in one patient nearly 30 years following implantation of radon seeds for the treatment of sarcoma of the pharynx; the presenting sign was hemorrhage from the posterior pharynx (Early et al, 1966).

A patient who had radon seeds implanted in both cheeks 25 years previously for the treatment of acne developed ulcerative radiation dermatitis (Auerbach & Pearlstein, 1973). Wearing unrefined gold rings made from decayed gold radon seeds or gold tubing from a radon plant has also caused radiation dermatitis (Simon & Harley, 1967).

The main concern with exposure to radon and its daughters is the development of lung cancer (Berger, 1990; HSDB , 2002; ATSDR, 1992). An increased risk of lung cancer has been clearly documented in uranium and certain other miners exposed to radon and its daughters, as well as in experimental animals (Berger, 1990; HSDB , 2002; (IARC, 1998); NIOSH, 1987).

An excess risk of mortality from non-malignant renal disease, with a particularly elevated risk of chronic and unspecified nephritis following a 10-year latent period, has been noted in underground uranium miners from the Colorado plateau area (BEIR IV, 1988).

Soluble uranium is nephrotoxic in experimental animals, but most of the uranium found in mines is in the form of less soluble uranium oxides (BEIR IV, 1988).

-FIRST AID

FIRST AID AND PREHOSPITAL TREATMENT

GENERAL -

Radon is not irritating, and there is no current evidence that it can cause toxicity or cancer following ingestion of the daughters either attached to airborne dust particles or in contaminated groundwater. Most exposure to radon involves chronic low level exposure and acute ingestion is unlikely. Routine use of gastrointestinal decontamination is not recommended.

-MEDICAL TREATMENT

LIFE SUPPORT

Support respiratory and cardiovascular function.

SUMMARY

FIRST AID - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Medical problems take priority over radiological concerns.
Use first aid treatment according to the nature of the injury.
Do not delay care and transport of a seriously injured person.
Give artificial respiration if victim is not breathing.
Administer oxygen if breathing is difficult.
In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes.
Injured persons contaminated by contact with released material are not a serious hazard to health care personnel, equipment or facilities.
Ensure that medical personnel are aware of the material(s) involved take precautions to protect themselves and prevent spread of contamination.

FIRST AID

INHALATION EXPOSURE -

INHALATION: Move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with an inhaled beta2-adrenergic agonist. Consider systemic corticosteroids in patients with significant bronchospasm.

DERMAL EXPOSURE -

DECONTAMINATION: Remove contaminated clothing and jewelry and place them in plastic bags. Wash exposed areas with soap and water for 10 to 15 minutes with gentle sponging to avoid skin breakdown. A physician may need to examine the area if irritation or pain persists (Burgess et al, 1999).

EYE EXPOSURE -

DECONTAMINATION: Remove contact lenses and irrigate exposed eyes with copious amounts of room temperature 0.9% saline or water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist after 15 minutes of irrigation, the patient should be seen in a healthcare facility.

ORAL EXPOSURE -

Most exposure to radon is chronic low-level exposure and acute ingestion is unlikely. Treatment of exposure should be symptomatic and supportive for patients demonstrating symptoms.

-RANGE OF TOXICITY

MINIMUM LETHAL EXPOSURE

Uranium miners exposed to 100 to 10,000 pCi radon-222/L in air died as a result of nonneoplastic respiratory diseases. Cumulative exposure to radon and radon daughters ranged from 50 WLM (Working Level Months) to greater than 3720 WLM. It should be noted, however, that in these studies, when considering the cause of these diseases, confounding factors such as exposure to other substances, history of smoking, etc., were not taken into account (ATSDR, 1990).

Several studies of uranium miners "indicate that lung cancer mortality was influenced by the total cumulative radiation exposure, by the age at first exposure, and by the timecourse of the exposure accumulation. Most deaths from respiratory cancers occurred 10 or more years after the individual began uranium mining" (ATSDR, 1990).

Researchers pooled information from 11 studies of radon-exposed miners and used various relative risk regression models that resulted in the following conclusions: "40% of all lung cancer deaths may be due to radon progeny exposure, 70% of lung cancer deaths in never-smokers, and 39% of lung cancer deaths in smokers. In the United States, 10% of all lung cancer deaths might be due to indoor radon exposure, 11% of lung cancer deaths in smokers, and 30% of lung cancer deaths in never-smokers" (Lubin, et al, 1995).

In an analysis of 11 studies of underground miners, researchers conclude that, in terms of cancers, the material risk of mortality from exposure to radon is linked to lung cancer only. The incidences of death due to leukemia and cancers of the liver and stomach are not related to cumulative exposure to radon and therefore are unlikely to have been caused by radon (Darby et al, 1995).

In one study, many more lung cancer deaths occurred at mine air concentrations of 30 pCi radon-222/L of air and greater. Miners were exposed to the radon for a minimum of 10 years with approximate cumulative exposure at 36 WLMs or more (ATSDR, 1990).

"Lung cancer is the only malignancy clearly associated with exposure to radon" (HSDB , 2002). Residential exposure to radon has been associated with as many as 20,000 lung cancer fatalities per year (NTP, 2001).

"There is sufficient evidence for the carcinogenicity of radon and its decay products in experimental animals [and] in humans. Radon and its decay products are carcinogenic to humans" (IARC, 1988) NTP, 2001).

MAXIMUM TOLERATED EXPOSURE

LEVEL OF EXPOSURE -

Calculated absorbed alpha radiation dose to basal cells in bronchial epithelium at a 0.2 Working Level Month (WLM) exposure to radon: 0.1 rad/year (adult men and women); 0.24 rad/year (children); 0.15 rad/year (infants) (Harley & Pasternack, 1982).
In one study of "high background" and "control" areas in China, it was concluded that excess lung cancers could not be separated from background normal fluctuations at radon exposures below cumulative 15 WLM (Hofmann et al, 1986).
The main floor household radon concentration is the primary determinant of body radon contamination in the general public; females may have higher body contamination than males, and nonsmokers may have more body contamination than smokers (Stebbings & Dignam, 1988).
Of 2552 uranium miners exposed to radon over an 8-year period in the 1950s, 419 had developed lung cancer by the end of 1995. Those miners exposed at younger ages were at higher risk to develop lung cancer. (Under age 30, risk increased by a factor of 2). Epidermoid tumors occurred more frequently in miners under the age of 30, while the risk of contracting the small cell type cancers was double that of the epidermoid tumors, but mostly occurred 5 to 14 years after radon exposure (Tomasek and Placek, 1999).
In one study, more than 8000 uranium miners were studied and after approximately 14 years, researchers found that 17 had lung cancer (the expected number was 2.21 (p > 0.05). The lung cancer risk to the miners appeared to be dependent upon the age at which they were first exposed to radon (HSDB, 2002).
Individuals who worked as uranium miners for 10 years or more and who were exposed to approximately 3.08 pCi/L air and thus 6.22 pCi radon-222/cm(2) skin surface area, had a statistically significant increase in the chance of developing a basal cell skin cancer. The researchers acknowledge that factors other than radon exposure may influence health outcomes (ATSDR, 1990).

ANIMAL DATA

In rats, the natural occurrence of lung cancer doubles following exposure to 20 WLM of radon and radon-daughter (HSDB , 2002).
In rats, exposure to radiation from radon and its daughters at 20 and 40 WLM caused an increased incidence of lung tumors (HSDB , 2002).

CARCINOGENICITY

Radon and its decay products are categorized in Group 1 (carcinogenic to humans) (IARC, 1988).
Radon and its isotopes (radon-222 and radon-220) are listed as Known to be Human Carcinogens (NTP, 2001).

Carcinogenicity Ratings for CAS10043-92-2 :

ACGIH (American Conference of Governmental Industrial Hygienists, 2010): Not Listed
EPA (U.S. Environmental Protection Agency, 2011): Not Listed
IARC (International Agency for Research on Cancer (IARC), 2016; International Agency for Research on Cancer, 2015; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010a; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2008; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2007; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2006; IARC, 2004): 1 ; Listed as: Radon-222 and its decay products

1 : The agent (mixture) is carcinogenic to humans. The exposure circumstance entails exposures that are carcinogenic to humans. This category is used when there is sufficient evidence of carcinogenicity in humans. Exceptionally, an agent (mixture) may be placed in this category when evidence of carcinogenicity in humans is less than sufficient but there is sufficient evidence of carcinogenicity in experimental animals and strong evidence in exposed humans that the agent (mixture) acts through a relevant mechanism of carcinogenicity.

NIOSH (National Institute for Occupational Safety and Health, 2007): Not Listed
MAK (DFG, 2002): Not Listed
NTP (U.S. Department of Health and Human Services, Public Health Service, National Toxicology Project ): K ; Listed as: Radon

K : KNOWN = Known to be a human carcinogen

TOXICITY AND RISK ASSESSMENT VALUES

EPA IRIS

EPA Risk Assessment Values for CAS10043-92-2 (U.S. Environmental Protection Agency, 2011):

Not Listed

TOXICITY VALUES

Reference: HSDB, 2002
- LD50- (INHALATION)MOUSE:

-STANDARDS AND LABELS

WORKPLACE STANDARDS

ACGIH TLV Values for CAS10043-92-2 (American Conference of Governmental Industrial Hygienists, 2010):

Not Listed

AIHA WEEL Values for CAS10043-92-2 (AIHA, 2006):

Not Listed

NIOSH REL and IDLH Values for CAS10043-92-2 (National Institute for Occupational Safety and Health, 2007):

Not Listed

OSHA PEL Values for CAS10043-92-2 (U.S. Occupational Safety, and Health Administration (OSHA), 2010):

Not Listed

OSHA List of Highly Hazardous Chemicals, Toxics, and Reactives for CAS10043-92-2 (U.S. Occupational Safety and Health Administration, 2010):

Not Listed

ENVIRONMENTAL STANDARDS

EPA CERCLA, Hazardous Substances and Reportable Quantities for CAS10043-92-2 (U.S. Environmental Protection Agency, 2010):

Listed as: Radionuclides (including radon)

Additional Information:

EPA CERCLA, Hazardous Substances and Reportable Quantities, Radionuclides for CAS10043-92-2 (U.S. Environmental Protection Agency, 2010):

Not Listed

EPA RCRA Hazardous Waste Number for CAS10043-92-2 (U.S. Environmental Protection Agency, 2010b):

Not Listed
Editor's Note: The D, F, and K series waste numbers and Appendix VIII to Part 261 -- Hazardous Constituents were not included. Please refer to 40 CFR Part 261.

EPA SARA Title III, Extremely Hazardous Substance List for CAS10043-92-2 (U.S. Environmental Protection Agency, 2010):

Not Listed

EPA SARA Title III, Community Right-to-Know for CAS10043-92-2 (40 CFR 372.65, 2006; 40 CFR 372.28, 2006):

Not Listed

DOT List of Marine Pollutants for CAS10043-92-2 (49 CFR 172.101 - App. B, 2005):

Not Listed

EPA TSCA Inventory for CAS10043-92-2 (EPA, 2005):

Not Listed

SHIPPING REGULATIONS

SURFACE

DOT -- Table of Hazardous Materials and Special Provisions (49 CFR 172.101, 2005):

Not Listed

ICAO International Shipping Name (ICAO, 2002):

Not Listed

LABELS

NFPA

NFPA Hazard Ratings for CAS10043-92-2 (NFPA, 2002):

Not Listed

-HANDLING AND STORAGE

SUMMARY

INDUSTRIAL CHEMICALS

The only method to determine whether or not potentially harmful radon concentration are present in a home is by direct measurement (ATSDR, 1990; (ATSDR, 2000)). Assessments of radon levels should be made so that efforts to reduce exposure can be undertaken, if necessary (ILO , 1998).

An initial radon measurement of 4 pCi/L should prompt additional measurements; above 4 pCi/L, additional measurements should be made within one year; at above 20 pCi/L, measure again within 3 months; and at 200 pCi/L, within one week (ATSDR, 1990).

Remediation is recommended for homes with airborne radon concentrations of greater than 4 pCi/L ((ATSDR, 2000)).

Advice should generally be sought before extensive and expensive abatement measures are taken. The EPA publishes two brochures called A CITIZEN'S GUIDE TO RADON and RADON REDUCTION METHODS: A HOMEOWNERS GUIDE containing general recommendations on home radon abatement, which should be available from either the Government Printing Office or the nearest EPA Regional Office (EPA, 1986) EPA, 1986a).

General mitigation measures include prevention of radon entry, dilution of indoor air with outdoor air, and various air treatments to remove radon gas or radon progeny (Nazroff & Nero, 1988).
Decisions to undertake mitigation measures in homes should generally be based on measured radon levels in the occupied portions (ACOEM, 1992).
Factors that should be considered in making decisions about home mitigation measures include (ACOEM, 1992):

Exposure dose
Number of home occupants
Personal health concerns
Cost of mitigation measures
Financial resources
Occupants' ages
Estimated achievable exposure reduction

The concentration of radon and its daughters in homes is greatly influenced by atmospheric pressure and effective ventilation (WHO, 1983). Energy conservation measures that decrease ventilation can be associated with increased radon concentrations in homes (HSDB , 2002). Sealing basement walls from which radon may leak is a recommended control method (ILO , 1998).

STORAGE

ROOM/CABINET RECOMMENDATIONS

Keep food out of areas where radon is known to be present (HSDB , 2002).
Ensure that areas where radon exists (eg, buildings, uranium mines) are properly ventilated (HSDB , 2002; ILO , 1998).

INCOMPATIBILITIES

Keep fluorine separate from areas containing radon (HSDB , 2002).

-PERSONAL PROTECTION

SUMMARY

RECOMMENDED PROTECTIVE CLOTHING - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Positive pressure self-contained breathing apparatus (SCBA) and structural firefighters' protective clothing will provide adequate protection against internal radiation exposure, but not external radiation exposure.

Where the potential for exposure to radon exists (ie, mining operations), persons should wear respiratory protection and wash their hands and faces thoroughly with copious amounts of soap and water before eating, drinking, and using toilet facilities (HSDB , 2002).

Miners should have access to showering facilities and to laundering and disposal services for their work clothing (HSDB , 2002).

RESPIRATORY PROTECTION

Refer to "Recommendations for respirator selection" in the NIOSH Pocket Guide to Chemical Hazards on TOMES Plus(R) for respirator information.

PROTECTIVE CLOTHING

CHEMICAL PROTECTIVE CLOTHING. Search results for CAS 10043-92-2.

Specific recommendations and test data for this chemical were not found in the available manufacturers' product literature. A complete list of consulted manufacturers and references is presented below.

ENGINEERING CONTROLS

Radon measurements were taken in various workplaces in Finland. In the workrooms assessed, the floors and walls were made mostly of concrete, with the ceilings made mostly of concrete, rock, or steel plate. In rooms where radon levels were high, successful remediation consisted of providing or upgrading ventilation systems and sealing foundations (Korhonen et al, 1997).

Mechanical exhaust ventilation and continuous operation of fans in the work area are recommended. Mines releasing exhaust outside of the facility must ensure that such operations conform to all applicable regulations (HSDB , 2002).

In buildings constructed of some types of granite, low-density concrete, or gypsum boards, the alpha radiation lung dose is greater (due to release of radon) than for individuals living in buildings made of other materials (Auxier, 1976).

Sealing such interior surfaces with an epoxy-based paint may decrease the potential for alpha radiation exposure (Auxier, 1976).
A multilayered seamless epoxy coating applied to the floor of a slab-on-grade building built over uranium mine tailings reduced the indoor radon concentration to less than that found in a similar building not built over mine tailings (Culot et al, 1978).

"In addition to increasing ventilation, radon control measures include sealing the foundation, subslab depressurization (creating negative pressure in the soil), pressurizing the home, and using air-cleaning devices. Methods of increasing ventilation include opening windows, ventilating basements and crawl spaces, ventilating sump-holes and floor drains to the outside of the house, and increasing air movement with ceiling fans. Ventilation must be modified properly, however, because increased ventilation can depressurize the house in some cases, causing an increase of soil gas entry to the home" ((ATSDR, 2000)).

Subslab depressuration is one of the most effective methods of reducing the level of radon in residences, decreasing radon levels by as much as 99 percent. Suction puts the soil at a lower pressure than the inside of the building, thus preventing inward migration of radon ((ATSDR, 2000)).

Prevention of soil gas entry into buildings is more effective than increased ventilation for reducing the levels of radon in buildings. This can be accomplished by sealing the foundation and depressurizing the soil. Vapor barriers around the foundation, sealing cracks and holes with epoxies and caulks, and sealing the crawl space from the rest of the house are recommended ((ATSDR, 2000)).

-PHYSICAL HAZARDS

FIRE HAZARD

SUMMARY

Editor's Note: This material is not listed in the Emergency Response Guidebook. Based on the material's physical and chemical properties, toxicity, or chemical group, a guide has been assigned. For additional technical information, contact one of the emergency response telephone numbers listed under Public Safety Measures.
POTENTIAL FIRE OR EXPLOSION HAZARDS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)
- Some of these materials may burn, but most do not ignite readily.
- Radioactivity does not change flammability or other properties of materials.
- Type B packages are designed and evaluated to withstand total engulfment in flames at temperatures of 800 degrees C (1475 degrees F) for a period of 30 minutes.

FLAMMABILITY CLASSIFICATION

NFPA Flammability Rating for CAS10043-92-2 (NFPA, 2002):

Not Listed

FIRE CONTROL/EXTINGUISHING AGENTS

FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Presence of radioactive material will not influence the fire control processes and should not influence selection of techniques.
Move containers from fire area if you can do it without risk.
Do not move damaged packages; move undamaged packages out of fire zone.

SMALL FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Dry chemical, CO2, water spray or regular foam.

LARGE FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Water spray, fog (flooding amounts).
Dike fire-control water for later disposal.

NFPA Extinguishing Methods for CAS10043-92-2 (NFPA, 2002):

Not Listed

DUST/VAPOR HAZARD

Radon reacts with fluorine to produce radon fluoride (HSDB , 2002).

Radon and its daughters are absorbed into the lungs by inhalation after becoming attached to airborne dust. Inhaled dust particles with attached radon daughters are distributed to the lungs, where the particles decay, resulting in radiation deposition. This has caused lung cancer in uranium miners and has been implicated in causing the same in persons whose homes have abundant amounts of radon and its daughters (ATSDR, 1990; Lewis, 2000).

REACTIVITY HAZARD

Radon reacts with fluorine to produce radon fluoride (HSDB , 2002).

Opening a 22-year-old glass ampoule which contained an aqueous solution of radon caused a great amount of pressure causing the top to eject with considerable force. This action probably was caused by hydrogen formation due to radiolysis of the solvent water (Urben, 1999).

EVACUATION PROCEDURES

SUMMARY

Editor's Note: This material is not listed in the Table of Initial Isolation and Protective Action Distances.

LARGE SPILL - PUBLIC SAFETY EVACUATION DISTANCES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

Consider initial downwind evacuation for at least 100 meters (330 feet).

FIRE - PUBLIC SAFETY EVACUATION DISTANCES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

When a large quantity of this material is involved in a major fire, consider an initial evacuation distance of 300 meters (1000 feet) in all directions.

PUBLIC SAFETY MEASURES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)

CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number:

MEXICO:

SETIQ:

01-800-00-214-00 in the Mexican Republic;
For calls originating in Mexico City and the Metropolitan Area: 5559-1588;
For calls originating elsewhere, call: 011-52-555-559-1588.

CENACOM:

01-800-00-413-00 in the Mexican Republic;
For calls originating in Mexico City and the Metropolitan Area: 5550-1496, 5550-1552, 5550-1485, or 5550-4885;
For calls originating elsewhere, call: 011-52-555-550-1496, or 011-52-555-550-1552; 011-52-555-550-1485, or 011-52-555-550-4885.

ARGENTINA:

CIQUIME:

0-800-222-2933 in the Republic of Argentina;
For calls originating elsewhere, call: +54-11-4613-1100.

BRAZIL:

PRÓ-QUÍMICA:

0-800-118270 (Toll-free in Brazil);
For calls originating elsewhere, call: +55-11-232-1144 (Collect calls are accepted).

COLUMBIA:

CISPROQUIM:

01-800-091-6012 in Colombia;
For calls originating in Bogotá, Colombia, call: 288-6012;
For calls originating elsewhere, call: 011-57-1-288-6012.

CANADA:

CANUTEC:

613-996-6666 (Collect calls are accepted);
*666 cellular (in Canada only).

UNITED STATES:

CHEMTREC®:

1-800-424-9300 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
703-527-3887 for calls originating elsewhere (Collect calls are accepted).

CHEM-TEL, INC.:

1-800-255-3924 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
813-248-0585 for calls originating elsewhere (Collect calls are accepted).

INFOTRAC:

1-800-535-5053 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
352-323-3500 for calls originating elsewhere (Collect calls are accepted).

3E COMPANY:

1-800-451-8346 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
760-602-8703 for calls originating elsewhere (Collect calls are accepted).

NATIONAL RESPONSE CENTER (NRC):

1-800-424-8802 - (24 hours) (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
202-267-2675 for calls in the District of Columbia.

MILITARY SHIPMENTS:

703-697-0218 - Explosives/ammunition incidents (Collect calls are accepted);
1-800-851-8061 - All other dangerous goods incidents.

NATIONWIDE POISON CONTROL CENTER (United States only):

1-800-222-1222 (Toll-free in the U.S.).

For additional details see the section entitled "WHO TO CALL FOR ASSISTANCE" under the ERG Instructions.
Priorities for rescue, life-saving, first aid, fire control and other hazards are higher than the priority for measuring radiation levels.
Radiation Authority must be notified of accident conditions. Radiation Authority is usually responsible for decisions about radiological consequences and closure of emergencies.
As an immediate precautionary measure, isolate spill or leak area for at least 25 meters (75 feet) in all directions.
Stay upwind.
Keep unauthorized personnel away.
Detain or isolate uninjured persons or equipment suspected to be contaminated; delay decontamination and cleanup until instructions are received from Radiation Authority.

AIHA ERPG Values for CAS10043-92-2 (AIHA, 2006):

Not Listed

DOE TEEL Values for CAS10043-92-2 (U.S. Department of Energy, Office of Emergency Management, 2010):

Not Listed

AEGL Values for CAS10043-92-2 (National Research Council, 2010; National Research Council, 2009; National Research Council, 2008; National Research Council, 2007; NRC, 2001; NRC, 2002; NRC, 2003; NRC, 2004; NRC, 2004; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; United States Environmental Protection Agency Office of Pollution Prevention and Toxics, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; 62 FR 58840, 1997; 65 FR 14186, 2000; 65 FR 39264, 2000; 65 FR 77866, 2000; 66 FR 21940, 2001; 67 FR 7164, 2002; 68 FR 42710, 2003; 69 FR 54144, 2004):

Not Listed

NIOSH IDLH Values for CAS10043-92-2 (National Institute for Occupational Safety and Health, 2007):

Not Listed

CONTAINMENT/WASTE TREATMENT OPTIONS

SUMMARY

SPILL OR LEAK PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)
- Do not touch damaged packages or spilled material.
- Damp surfaces on undamaged or slightly damaged packages are seldom an indication of packaging failure. Most packaging for liquid content have inner containers and/or inner absorbent materials.
- Cover liquid spill with sand, earth or other non-combustible absorbent material.
RECOMMENDED PROTECTIVE CLOTHING - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 163 (ERG, 2004)
- Positive pressure self-contained breathing apparatus (SCBA) and structural firefighters' protective clothing will provide adequate protection against internal radiation exposure, but not external radiation exposure.

WASTE TREATMENT OPTIONS

CHEMICAL TREATMENT

Areas where radium is used or stored should be well ventilated to prevent buildup of hazardous radon levels (Lewis, 2000).
Waste management activities associated with material disposition are unique to individual situations. Proper waste characterization and decisions regarding waste management should be coordinated with the appropriate local, state, or federal authorities to ensure compliance with all applicable rules and regulations.

PHYSICAL TREATMENT

The short half-life of radon enables it to be compressed and stored in tanks until it breaks down. Activated charcoal can be used to absorb small amounts of radon. Detention chambers, adsorbent beds, and liquefaction columns may be used to remove particulate matter from gases. Following filtration, radioactive particulates that remain may be released into the atmosphere (ATSDR, 1990).
Low-level radioactive waste (eg, paper towels, protective clothing, rags, animal excreta, and animal carcasses) should be accumulated in appropriate containers and incinerated with the resulting ashes either being dispersed to the atmosphere or packaged for disposal to the sea or the ground (ATSDR, 1990).

-ENVIRONMENTAL HAZARD MANAGEMENT

POLLUTION HAZARD

"Radon is considered the most prevalent source of natural radiation. Together with its 'daughters,' or radionuclides formed by its disintegration, radon constitutes approximately three fourths of the effective equivalent dose to which humans are exposed due to natural terrestrial sources" (ILO , 1998).

Both uranium-238 and radium-226 occur naturally in most soils and rock (Berger, 1990).

Radon sources include soil, water, including groundwater, and natural gas (radon enters these through subsoil), outside air, and common construction materials such as granite, pumice stone, wood, bricks, and cinder blocks. Other pollution sources include manufacturing of construction materials using alum slate; the use of by-products from phosphate minerals treatment and aluminum production; ash use following coal combustion; and slag and dross use following iron ore treatment using blast furnaces (ILO , 1998).

The radon decay product exits the soil or rock as it is formed, and becomes ubiquitous in the environment (Berger, 1990). Higher radon concentrations are produced in areas with richer sources of the precursor radionuclides, especially when poor ventilation is present (Berger, 1990).

Radon accumulations can occur in well-insulated buildings located in areas with soil concentrations of uranium, thorium ore deposits, and granite formations. Primary hazards associated with this isotope exist during the inhalation of gaseous element and its solid daughters, which are collected on normal dusts in the air (ATSDR, 1990; (ATSDR, 2000); Lewis, 2000). In approximately one month, radon and its daughters build up to an equilibrium value from radium compounds (Lewis, 2000).

Granites often contain more uranium and radium than other types of rock (Archer, 1987). The Reading Prong is a precambrian geologic structure consisting of mostly quartzo-feldspathic gneiss (granites) with small interlayers of amphibolite and marble (Archer, 1987).

In buildings constructed of some types of granite, low-density concrete, or gypsum boards, the alpha radiation lung dose is greater (due to release of radon) than for individuals living in buildings made of other materials (Auxier, 1976).

Radon levels may be especially high in buildings with unpaved crawl spaces (Cohen, 1980). Increased insulation that reduces air exchange may increase indoor radon levels by a factor of 2.5 or more (Cohen, 1980).

Airborne levels of radon in homes tend to be high when radon in the water supply is high, although this may reflect high concentrations of radon in soil-gas (Hess et al, 1983).

In European dwellings, the major source of indoor radon may be the construction materials; in the US, most of the indoor radon in dwellings is due to penetration of radon soil-gas (Steinhausler et al, 1983).

In some locations, landfills containing uranium tailings have been filled in and built on, therefore increasing the possibility of radon exposure (ATSDR, 1990).

The type of soil and underlying bedrock will determine the levels of radon in ambient air (ATSDR, 1990). Estimates are that 1 gram of radium exists in each square mile of soil (6 inches deep). From this radon is released to the atmosphere in very small amounts (HSDB , 2002).

AMBIENT AIR LEVELS

The average ambient air level is one part radon to 1X10(21) parts of air (HSDB , 2002).
Typical outdoor air radon levels are approximately 0.2 pCi/L (7 Bq/m(3)) (Hart et al, 1989).

The mean atmospheric radon level in the contiguous United States is 0.25 pCi radon-222/L of air (9 Bq/m(3)). Radon levels in the Colorado Plateau measure up to 0.75 pCi radon-222/L (30 Bq/m(3)) (ATSDR, 1990).

In the most comprehensive and most often cited study of indoor air in the United States, the average radon concentration was found to be 1.5 pCi/L of air (ATSDR, 1990). On ground level, aeration of radon levels is high in fall and winter and low in spring and summer (HSDB , 2002).
An EPA estimate identifies approximately six million homes in the United States as having radon levels greater than 4 pCi/L of air ((ATSDR, 2000)).

The percentage of radon gas in the earth's atmosphere is 6X10(-18) (Baxter et al, 2000).

Radon is emitted by plants through evapotranspiration. Groundwater is the second largest source of radon releases to the atmosphere (5x10(8) Ci or 1.85x10(19) Bq radon-222/year, globally) (ATSDR, 1990).

In the United States, large aquifers have radon concentrations averaging 240 pCi radon-222/L (8.8 Bq/L) of water, while smaller aquifers have much higher concentrations of 780 pCi radon-222/L (28.9 Bq/L) (ATSDR, 1990).

Drinking water supplies also contribute to environmental exposure to radon, with exposure levels averaging 100 to 600 pCi (3.7 to 22.2 Bq) from both ingestion and inhalation of radon in drinking water (ATSDR, 1990).

ENVIRONMENTAL FATE AND KINETICS

The ultimate fate process for radon is radioactive decay. Since there are no sinks for radon, only small amounts are lost to the stratosphere. "Therefore, degradation proceeds by alpha-emission to form polonium-218. The half-lives of the progeny are much shorter, ranging from approximately 0.0002 seconds for polonium-214 to 30 minutes for lead-214" (ATSDR, 1990). In indoor air, radon transport is almost entirely controlled by ventilation rates in the enclosure. As ventilation rates decrease, indoor air concentrations increase (ATSDR, 1990).
The release of radon from the pore space or soil gas to ambient aur is called exhalation (ATSDR, 1990). Rain, snow, freezing, and changes in atmospheric pressure will affect exhalation, and therefore, diffusion rates. Lower radon exhalation rates occur when the parameters affecting them, mentioned above, increase. Radon exhalation rates can range from 0.0002 to 0.07 Bq/m(2)/sec (HSDB , 2002).

WATER

SURFACE WATER
- Radon in groundwater moves via the natural water flow and also by diffusion. Since radon has a low solubility in water and a relatively short half-life (3.823 days), most of it will decay before it can be released. The small amount that is released to the atmosphere will be lost by radioactive decay, however, since there are no sinks for radon, only small amounts are lost to the stratosphere (ATSDR, 1990).

SOIL

TERRESTRIAL
- Since radon is a gas, its occurrence in soil is referred to as "soil-gas," which is the gas or water-filled space between individual particles of soil. Radon travels via alpha recoil from soil particles into these pore spaces. Once in the pore spaces, radon moves by way of diffusion, convection, and flow of groundwater and rain. In soil, radon is released to the air through exhalation and then is lost by radioactive decay. However, since there are no sinks for radon, only small amounts are lost to the stratosphere (ATSDR, 1990).
- "High porosity increases the diffusion rate. The release rate from a material depends also on its moisture content: if the moisture content is very low the radon release is decreased by the effect of re-adsorption of radon atoms on surfaces in the pores. If the moisture content increases slightly, the radon release increases up to a certain moisture content, above which the release of radon decreasing again owing to a decreasing diffusion rate in water filled pores" (HSDB , 2002).
- "The mechanism of radon release from rock, soil, and other materials is not very well understood and is probably not always the same. The main physical phenomena are recoil and diffusion of the radon atom through imperfections of the crystalline structures of the radium bearing particle followed by a secondary diffusion, which depends on the porosity of the material" (HSDB , 2002).
- Radon-222 fluence rate and several environmental variables were measured on two plots with uranium mill tailings buried beneath 30 centimeters of overburden and 20 centimeters of topsoil. An additional 30 centimeters of clay covered the tailings on one plot and each plot was subdivided into bare soil and vegetated subplots. The most important effect on radon-222 fluence rates from these plots was the combination of a clay cap and a vegetated surface (Morris & Fraley Jr, 1989).
- In a study of genetically related pairs of radionuclides (radium-226 and radon-222) in soils and the aboveground phytomass of plants, it was determined that the noted absence of balance between radon-222 and radium-226 in plants as well as higher radon-222/radium-226 ratios in the above-ground phytomass as compared to that of the root-containing soil layer (25- to 185-fold) appeared to be accounted for by the root pathway of radon-222 uptake and transport of this radionuclide to aboveground plants' organs (Taskayev et al, 1986).

OTHER

OTHER
- HALF-LIVES

ENVIRONMENTAL TOXICITY

No information found at the time of this review.

-PHYSICAL/CHEMICAL PROPERTIES

MOLECULAR WEIGHT

222.0176 (atomic mass 222Rn)

DESCRIPTION/PHYSICAL STATE

Radon exists as a colorless, tasteless, odorless, inert, very dense, monotomic radioactive gas (Budavari, 2000; (Lewis, 1998; Lewis, 2000; Lewis, 2001). Radon "can be condensed to a colorless, transparent liquid and to an opaque, glowing solid" (Lewis, 2001). Radon is an inert gas at temperatures greater than -61.8 degrees C (Berger, 1990) and is the heaviest known gas (Lewis, 2001).

The solid form exists as cube-shaped, face-centered crystals (Budavari, 2000).

"When cooled below the freezing point, radon exhibits a brilliant phosphorescence which becomes yellow as the temperature is lowered and orange-red at the temperature of liquid air" (HSDB , 2002).

VAPOR PRESSURE

395.2 mmHg (at -71 degrees C) (ATSDR, 1990)

SOLID (HSDB , 2002)

1 Pa (at -163 degrees C)
10 Pa (at -152 degrees C)
100 Pa (at -139 degrees C)
1 kPa (at -121.4 degrees C)
10 kPa (at -97.6 degrees C)

DENSITY

STANDARD TEMPERATURE AND PRESSURE

(0 degrees C; 32 degrees F and 760 mmHg)
GAS: 9.73 g/L (Lewis, 1996)

OTHER TEMPERATURE AND/OR PRESSURE

GAS: 9.72 g/L (at 0 degrees C) (Lewis, 2001)
GAS: 9.73 kg/m(3) (at 0 degrees C and 101.3 kPa) (Budavari, 2000)
GAS: 9.96X10(-3) g/cm(3) (at 20 degrees C) (ATSDR, 1990)
LIQUID: 4.4 g/L (at -62 degrees C) (Lewis, 2000)

FREEZING/MELTING POINT

MELTING POINT

-71 degrees C (ATSDR, 1990; HSDB , 2002)

BOILING POINT

-62 degrees C (Lewis, 2000)

-61.8 degrees C (ATSDR, 1990)

SOLUBILITY

IN WATER

GAS: 230 cm(3)/L (at 20 degrees C) (Budavari, 2000)
51.0 cm(3)/100 cc water (at 0 degrees C) (HSDB , 2002)
22.4 cm(3)/mL water (at 25 degrees C) (HSDB , 2002)
0.326 mL/mL water (at 10 degrees C) (HSDB , 2002)
0.222 mL/mL water (at 20 degrees C) (HSDB , 2002)
0.162 mL/mL water (at 30 degrees C) (HSDB , 2002)
0.126 mL/mL water (at 40 degrees C) (HSDB , 2002)
0.085 mL/mL water (at 60 degrees C) (HSDB , 2002)
13 m(3)/100 m(3) water (at 50 degrees C) (HSDB , 2002)

IN ORGANIC SOLVENTS

Radon is soluble in organic solvents (Budavari, 2000).
Radon is slightly soluble in alcohol and organic liquids (ATSDR, 1990; HSDB , 2002).

OTHER/PHYSICAL

CRITICAL PRESSURE

6280 kPa (Budavari, 2000)

CRITICAL TEMPERATURE

378 degrees K (Budavari, 2000)

HEAT OF FUSION

3247 J/mol (Budavari, 2000; (HSDB , 2002)

VISCOSITY

23.3 Pa.s (gas at 101.32 kPa and 25 degrees C) (HSDB , 2002)

-REFERENCES

GENERAL BIBLIOGRAPHY

40 CFR 372.28: Environmental Protection Agency - Toxic Chemical Release Reporting, Community Right-To-Know, Lower thresholds for chemicals of special concern. National Archives and Records Administration (NARA) and the Government Printing Office (GPO). Washington, DC. Final rules current as of Apr 3, 2006.

40 CFR 372.65: Environmental Protection Agency - Toxic Chemical Release Reporting, Community Right-To-Know, Chemicals and Chemical Categories to which this part applies. National Archives and Records Association (NARA) and the Government Printing Office (GPO), Washington, DC. Final rules current as of Apr 3, 2006.

49 CFR 172.101 - App. B: Department of Transportation - Table of Hazardous Materials, Appendix B: List of Marine Pollutants. National Archives and Records Administration (NARA) and the Government Printing Office (GPO), Washington, DC. Final rules current as of Aug 29, 2005.

49 CFR 172.101: Department of Transportation - Table of Hazardous Materials. National Archives and Records Administration (NARA) and the Government Printing Office (GPO), Washington, DC. Final rules current as of Aug 11, 2005.

62 FR 58840: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 1997.

65 FR 14186: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2000.

65 FR 39264: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2000.

65 FR 77866: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2000.

66 FR 21940: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2001.

67 FR 7164: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2002.

68 FR 42710: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2003.

69 FR 54144: Notice of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances - Proposed AEGL Values, Environmental Protection Agency, NAC/AEGL Committee. National Archives and Records Administration (NARA) and the Government Publishing Office (GPO), Washington, DC, 2004.

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Culot MVJ, Schiager KJ, & Olson HG: Development of a radon barrier. Health Physics 1978; 35:375-380.

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Classification | Information to evaluate chemical incidents

Information to evaluate chemical incidents

Information to evaluate chemical incidents

Information to evaluate chemical incidents