The GRANULAR type is available in resin grades of agglomerates, coarse, finely divided, and presintered.

GRANULAR types may be processed by molding, preforming, sintering, and ram extrusion, and are used for the production of gaskets, packing, seals, wrappings, electronic components, bearings, molded sheets, rods, heavy-walled and other tubing, tapes, and molded shapes for a variety of applications including chemical, electrical, mechanical, and nonadhesive (adherent) products.

FINE POWDER types are used for the production of wire coating, thin-walled and other tubing, pipe, overbraided hose, spaghetti tubing, thread-sealant tape, pipeliners, and porous structures.

DISPERSION types are used in the production of impregnation materials, coatings, packing, film, and bearings.

Teflon is inert under ordinary conditions (Budavari, 1996).

Depending on the temperature of thermal decomposition, a variety of oxidized products containing fluorine, carbon, and oxygen -- including carbonyl fluoride and hydrogen fluoride -- may be released from Teflon (Sittig, 1985; Proctor et al, 1988). There is no evidence that Teflon produces decomposition products at temperatures below 200 degrees C (ILO, 1983).

At temperatures of 315 to 375 degrees C and up to 500 degrees C, Teflon decomposition products are primarily the monomer tetrafluoroethylene, perfluoroisopropylene, other C4-C5 perfluoro-compounds, and an unidentified waxy particulate fume (which may be the etiologic agent for polymer fume fever) (Proctor et al, 1988).

At temperatures above 400 degrees C, the principle toxic decomposition products of Teflon are PERFLUOROISOBUTYLENE and CARBONYL FLUORIDE (Okawa & Polakoff, 1974).

At decomposition temperatures of 500 to 800 degrees C, the principal decomposition product is CARBONYL FLUORIDE, which is hydrolyzable to CARBON DIOXIDE and HYDROGEN FLUORIDE (Proctor et al, 1988).

Particulates, possibly with adsorbed toxic substances, were produced when Teflon was heated to less than 500 degrees C (Clayton & Clayton, 1982). Carbonyl fluoride was the principle decomposition product at temperatures of between 500 and 650 degrees C (Clayton & Clayton, 1982). At temperatures greater than 650 degrees C, carbon tetrafluoride and carbon dioxide were the principal decomposition products (Clayton & Clayton, 1982).

Normal cooking use of Teflon-coated pans does not present a danger to either pet birds or humans, but gross overheating can poison birds, which are more susceptible to the toxicity of the decomposition products (Griffith et al, 1973; Wells et al, 1982). Self-cleaning oven operation has also been fatal to pet birds caged near the oven (Stoltz et al, 1992).

Accidental overheating has resulted in polymer fume fever which cleared in 24 hours in one human case (Blandford et al, 1975).

RATS - The LC50 in rats for a 4-hour inhalation exposure varies from 40,000 ppm for the tetrafluoroethylene monomer to 0.76 ppm for perfluoroisobutylene (ILO, 1983).

BIRDS - Birds are more susceptible to the toxic effects of Teflon decomposition products than humans (Griffith et al, 1973).

The Teflon decomposition product perfluoroisobutylene is the most toxic of the known fluoroalkene compounds, and has a toxicity 10 times greater than that of phosgene in experimental animals (Ellenhorn & Barceloux, 1988; Waritz & Kwon, 1968), with a 6-hour inhalation exposure to 0.5 ppm being lethal (Waritz & Kwon, 1968).

In inhalation experiments with perfluoroisobutylene, rats were given nose-only exposure to various concentrations for between 0.25 and 10 minutes (Smith et al, 1982). LC50's were calculated for a 0.25-minute exposure (361 ppm) and a 10-minute exposure (17 ppm).

The development of weight loss and pulmonary impairment was seen up to 48 hours after the exposure. Affected animals either died with pulmonary congestion or recovered completely without apparent sequelae (Smith et al, 1982).

Rats and mice were killed by a 2-hour inhalation exposure to 0.018 or 0.015 mg/L of perfluoroisobutylene (Karpov, 1963).

It has been proposed that peroxyl radicals generated during combustion of perfluoro polymers (e.g., polytetrafluoroethylene) may play a role in pulmonary toxicity (Pryor et al, 1990).

3 : The agent (mixture or exposure circumstance) is not classifiable as to its carcinogenicity to humans. This category is used most commonly for agents, mixtures and exposure circumstances for which the evidence of carcinogenicity is inadequate in humans and inadequate or limited in experimental animals. Exceptionally, agents (mixtures) for which the evidence of carcinogenicity is inadequate in humans but sufficient in experimental animals may be placed in this category when there is strong evidence that the mechanism of carcinogenicity in experimental animals does not operate in humans. Agents, mixtures and exposure circumstances that do not fall into any other group are also placed in this category.

Monitoring urinary fluoride levels might be used as an indication of exposure (Clayton & Clayton, 1982).

Workplace ventilation recommendations have been made for operations involving thermal processing of Teflon (Clayton & Clayton, 1982):

TEEL-0: The threshold concentration below which most people will experience no adverse health effects.

TEEL-1: The airborne concentration (expressed as ppm [parts per million] or mg/m(3) [milligrams per cubic meter]) of a substance above which it is predicted that the general population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic, nonsensory effects. However, these effects are not disabling and are transient and reversible upon cessation of exposure.

TEEL-2: The airborne concentration (expressed as ppm or mg/m(3)) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long-lasting, adverse health effects or an impaired ability to escape.

TEEL-3: The airborne concentration (expressed as ppm or mg/m(3)) of a substance above which it is predicted that the general population, including susceptible individuals, could experience life-threatening adverse health effects or death.