Decomposition Products of Teflon
The chemicals identified are from the abstracts listed
• Information on Molecular formula, Structure, and
Other Names are from Toxnet's
are two CAS Numbers for Carbonyl fluoride. Both have been
cited as Teflon thermal decomposition products
also known as
Carbon difluoride oxide
Carbon fluoride oxide (COF2)
Carbon oxyfluoride (COF2)
from this website
little information available. Note the synonyms for Carbonyl
difluoride (above): Fluophosgene
citations using this synonym. The primary name is Perfluorisobutylene]
the primary name is Perfluorisobutylene.
to as "oxyfluorides
Oxygen fluoride (OF2)
Toxicology of Perfluoroisobutene by Jiri Patocka and
... is a fluoro-olefin produced by thermal decomposition
of polytetrafluoroethylene (PTFE), e.g., Teflon .
of PTFE generates fumes of highly toxic PFIB and poses
a serious health hazard to the human respiratory tract.
PFIB is approximately ten times as toxic as phosgene .
Inhalation of this gas can cause pulmonary edema, which
can lead to death. PFIB is included
in Schedule 2 of the Chemical Weapons Convention (CWC),
as a result of the prompting by one delegation to the
Conference on Disarmament . The aim of the inclusion
of chemicals, such as PFIB was to cover those chemicals,
which would pose a high risk to the CWC. Subsequently
PFIB, specifically, was included in the final text of
PFIB is a strong electrophile, which reacts with all nucleophiles
. The high electrophilicity of PFIB is a result of
the strong electron-attracting effects of the fluorine
atoms of the trifluoromethyl groups and the conjugation
of the fluorine’s p electrons with the double bond
of the vinyl group. Several reactive intermediate species
were identified in the reaction of PFIB with nitrone and
nitroso spin trap agents, and, some of the expected reactive
nucleophiles in vivo include amines, alcohols and especially
decomposes rapidly when dissolved in water, forming various
reactive intermediates and fluorophosgene, which then
decomposes into carbon dioxide, a radical anion and hydrogen
fluoride . PFIB is a gas with a boiling point of 7.0çC
at one atm and a gas density of 8.2 g/L . The synthesis
of PFIB from fluorodichloromethane is given in Fig. 1.
The toxicity of PFIB may be correlated with its susceptibility
to nucleophilic attack and the generation of reactive
intermediates . This is similar to the toxicity of
other fluoro-olefins; their toxicity is directly proportional
to the reactivity of that olefin with nucleophiles [7,
Toxicity. The median lethal concentration (LC50) in single
exposures of rats was 0.5 ppm. The intoxicated rats either
died with gross pathological signs of pulmonary congestion
or recovered with no apparent residual effects. The 15-second
LC50 was 361 ppm and the 10-minute LC50 was 17 ppm .
Similar high acute toxicity following inhalation was seen
in other species with a two hour LC50 in mice reported
to be either 1.6 ppm  or 0.98 ppm , in rabbits
either 4.3 ppm  or 1.2 ppm , in guinea-pigs 1.05
ppm  and in cats 3.1 ppm . In experiments in which
rats were exposed to a concentration of 12.2 ppm for 10
min, an unusual postexposure latency period of approximately
8 hours was observed prior to the occurrence of pulmonary
1. Zeifman, Y.B., Ter-Gabrielyan, N.P., Knunyants, I.L.
The Chemistry of Perfluoroisobutylene. Uspekhi Khimii,
1984; 53: 431-461.
2. Oberdorster, G., Ferin, J., Gelein, J., Finkelstein,
R., Baggs, R., Effects of PTFE Fumes in the Respiratory
Tract: A Particle Effect? Aerospace Medical Assiciation
65th Annual Scientific Meeting, 1994; 538: A52.
3. CD/CW/WP.239. Verification of the Nonproduction of
Chemical Weapons: An Illustrative Example of the Problem
of Novel Toxic Chemicals. 12 April 1989.
4. England, D.C., Krespan, C.G. Fluoroketenes. I. Bis(trifluoromethyl)ketene
and Its Reaction with Fluoride Ion. J Am Chem Soc, 1966;
5. Arroyo, C.M. The Chemistry of Perfluoroisobutylene
(PFIB) with Nitrone and Nitroso Spin Traps: an EPR/Spin
Trapping Study. Chem Biol Interact 1997; 105: 119-129.
6. Lailey, A.F., Hill, L., Lawston, I.W., Stanton, D.,
Upshall, D.G. Protection by Cysteine Esters Against Chemically
Induced Pulmonary Oedema. Biochem Pharmacol 1991; 42:
7. Cook, E.W., Pierce, J.S. Toxicology of Fluoro-Olefins.
Nature 1973; 242: 337-338.
8. Clayton, J.W. Toxicology of the Fluoroalkenes. Review
and Research Needs. Environ Health Perspect 1977; 21:
9. Smith, L.W., Gardner, R.J., Kennedy, G.L., Jr. Short-Term
Inhalation Toxicity of Perfluoroisobutylene. Drug Chem
Toxicol 1982; 5: 295-303.
10. Karpov, B.D. Determination of Upper and Lower Parameters
of Perfluoroisobutylene Toxicity. Tr. Leningr Sanit Gig
Med Inst 1975; 30: 111-120.
11. Paulet, G., Bernard, J.P. High Boilers Appearing During
the Production of Polyfluorethylene. Biol Med 1968; 57:
12. Lehnert, B.E., Archuleta, D., Gurley, L.R., Session,
W., Behr, M.J., Lehnert, N.M., Stavert, D.M. Exercise
Potentiation of Lung Injury Following Inhalation of a
Pneumoedematogenic Gas: Perfluoroisobutylene. Exp Lung
Res 1995; 21: 331-350.
Toxicology of Perfluoroisobutene by Jiri Patocka and Jiri
Bajgar (Department of Toxicology, Military Medical Academy
500 01 Hradec, Czech Republic). The ASA Newsletter (Applied
Science and Analysis, Inc.). 1998.
Teflon (9002-84-0), a physically inert tetrafluoroethylene (116-14-3)
resin, is discussed in a paper presented at the American Industrial
Annual Meeting in Cincinnati, Ohio on April 26, 1955, and it is
noted that its pyrolytic products are toxic, and exposure to various
mixtures of them will induce polymer fume
fever in humans. The latter influenza like syndrome has
not been reproduced in animals. Sufficiently intense exposure
of animals to Teflon's thermal products, however, is generally
lethal. The associated evidence of pulmonary edema, together with
other early test results, originally suggested that hydrogen fluoride
(7664-39-3) (HF) was the responsible toxic agent. The pyrolysis
of Teflon starts at 200 degrees-C and proceeds slowly up to 420
degrees-C; at 500 to 550 degrees-C, the degradational weight loss
reaches 10% to 5% per hour, respectively, depending on conditions.
In the temperature range 300 to 360 degrees-C, hexafluoroethane
(C2F6) and octafluorocyclobutane
(C4F8) were identified as decomposition
the range 380 to 400 degrees-C, octafluoroisobutylene
(also C4F8) could be detected and, at 500 to 550 degrees-C,
the chief pyrolysis products other than tetrafluoroethylene
(116-14-3) (C2F4) were hexafluoropropylene
(116154), (C3F6) octafluorocyclobutane, and octafluoroisobutylene
plus a complex residue of perfluoroolefins. Inhalation
toxicity tests indicated that the octafluoroisobutylene
gas, the most potent product, was approximately ten times as toxic
as phosgene (75-44-5).
The rat mortality factor seemed to be proportional to the product
of exposure time and Teflon surface area as a function of pyrolysis
temperature. Teflon 6, a lower molecular weight polymer than Teflon
1, produced more toxic pyrolysis products. Other kinds of industrial
polymers were observed to produce lethal atmospheres under less
drastic conditions than either form of Teflon.
Toxicity of Pyrolysis Products of "Teflon" Tetrafluoroethylene
Resin by Zapp JA Jr, Limperos G, Brinker KC. Proceedings of the
American Industrial Hygiene Association Annual Meeting, Cincinnati,
Ohio, April 26, 1955.
Abstract: The toxic
properties of the tetrafluoroethylene (9002-84-0)
monomer and of products of the thermal treatment of the tetrafluoroethylene
polymer in acute experiments on cats, rabbits, albino rats and
albino mice are reported. In rats and rabbits
the inhalation of monomer induced hyperemia of organs, especially
the brain, hemorrhage in the spleen and lungs, and dystrophic
changes in the kidneys. Emphysema
and atelectasis was observed in the lungs, desquamation of the
epithelium in the bronchi also was observed. The threshold mortality
for the monomer was 2.5 volume percent for albino rats and 4.0
volume percent for rabbits. The pyrolytic decomposition of tetrafluoroethylene
polymer was lethal to cats, rabbits, mice, and rats. Death was
caused by acute pulmonary edema, sometimes accompanied by pneumonia.
Renal dystrophy was observed in the cats. There was acute irritation
of the upper respiratory tract mucosa in all test animals. It
is concluded that the pathology observed upon inhalation
of the products of thermal decomposition of the polymer is apparently
explained by the presence in the pyrolyses gas of difluorophosgene,
and other highly toxic hydrocarbons. (Russian: English translation
Ref: Toxicity of Tetrafluoroethylene
by Zhemerdi A. Trudy Leningradskogo Sanitarno-gigienicheskogo
Meditsinskogo Instituta, Vol. 44, pages 164-176, 1958. Document
Toxic effects following inhalation exposure to polytetrafluoroethylene
(9002-84-0) (PTFE) pyrolysis products were determined in rats.
Greenacres-Flora-rats were exposed to PTFE pyrolysis products
containing hydrolyzable fluoride equal to 50 parts per million
of carbonyl fluoride (353-50-4) for 1 hour daily for 5 days. On
day 1 and 5 of the exposure period, and 3, 7, and 18 days postexposure
urine samples were collected and examined for fluoride excretion
and glucose, protein, and ketones. On each of those days, a test
animal was killed, and kidney and lung tissues were tested for
succinic-dehydrogenase activity. Weight changes and mortality
during the course of the experiment were also noted. During the
5 exposure days and shortly afterwards, mortality reached 22 percent,
although the total exposure dose was less than half the median
lethal dose for one exposure. Daily
urinary fluoride excretion jumped to 14 times normal on the first
exposure day and remained at 4 times normal by the eighteenth
postexposure day. By
the fifth exposure day, body weights dropped 30 percent, urine
glucose, protein, and ketones were abnormal, and succinic-dehydrogenase
activity dropped to near zero in the kidney and had more than
doubled in the lung; by the eighteenth post exposure day, these
values had returned to normal. The
authors conclude that carbonyl
fluoride generated during the pyrolysis
of PTFE hydrolyzes in body fluids and produces fluoride toxicity.
cumulative effect of repeated exposures is much more toxic than
a single equivalent exposure. If death does not result, the metabolic
inhibition due to fluoride poisoning is completely reversible.
Biochemical Changes Associated with Toxic Exposures to Polytetrafluoroethylene
Pyrolysis Products by Scheel LD, McMillan L, Phipps FC. American
Industrial Hygiene Association Journal, Vol. 29, No. 1, pages
The pathologic effects of exposure to combustion
products of polytetrafluoroethylene (9002-84-0) (PTFE)
were studied in rats. Fischer-344-rats received single 30 minute
exposures to concentrations from 0.005 to 5.025 milligrams per
liter aerosol products of PTFE heated to 595 degrees-C. The median
lethal concentration (LC50) was determined. Necropsies were performed
at 0, 2, 12, 24, and 36 hours post exposure or between 2 and 17
days. The LC50 for thermal degradation products of PTFE was 0.045
milligrams per liter. Conjunctival erythema
and serous occular and nasal discharge were seen in survivors
immediately after exposure. Lesions were
found in lungs of 84 percent of exposed rats. Focal hemorrhages,
edema, and fibrin deposition in the lungs were found. Focal interstitial
thickenings developed and increased. Alveolar macrophages became
more severe up to 96 hours. Thrombosis or embolism of pulmonary
capillaries and veins were found in 38 percent of exposed rats.
The degree of pathologic change increased as the dose increased
up to the LC50, but fluctuated above that. Disseminated intravascular
coagulation occurred in 53 percent of exposed rats and was positively
related to the amount of lung damage. Renal infarcts due to disseminated
intravascular coagulation were found but no other kidney lesions
were seen. The authors conclude that disseminated intravascular
coagulation appears to be a consequence of exposure to PTFE combustion
Pathologic Findings In Rats Following Inhalation Of Combustion
Products Of Polytetrafluoroethylene (PTFE) by Zook BC, Malek DE,
Kenney RA. Toxicology, Vol. 26, No. 1, pages 25-36, 1983.
is a thermal decomposition product
It has many synonyms; it's
primary name is
(CAS No. 7783-41-7).
The molecular structure is:
the US National Institute for Occupational Safety and
Health (NIOSH) category of
Dangerous to Life or Health Concentrations (IDLH)
a list of 387 workplace chemicals - the
two chemicals that share the rank of most dangerous chemicals
for "respirator selection criteria" are:
difluoride : IDLH of 0.5 ppm
Lithium hydride : IDLH of 0.5 mg/m3
difluoride is a strong irritant
to the entire respiratory tract and causes pulmonary edema
and hemorrhage when inhaled for a few hours at 0.5 ppm
[Deichmann and Gerarde 1969].
for original (SCP) IDLH: The
chosen IDLH is based on the statements by Deichmann and
Gerarde  that oxygen
difluoride is a strong irritant to the entire respiratory
tract and causes pulmonary edema and hemorrhage when inhaled
for a few hours at 0.5 ppm. Development of
pulmonary signs leading to death may be delayed several
hours after the exposure [Deichmann and Gerarde 1969].
In addition, AIHA  reported that the Committee
on Toxicology of the National Research Council recommended
an Emergency Exposure Limit (EEL) of 0.5 ppm for
a 10-minute exposure. This EEL is supposed to be for exposures
that are "rare in the lifetime of an individual and
permit some degree of reversible injury short of incapacitation"
Lethal concentration data:
0.5-hr LC (CF)
et al. 1972
et al. 1972
et al. 1972
et al. 1972
. Oxygen difluoride. In: Hygienic guide series.
Am Ind Hyg Assoc J 28:194-196.
KI Jr, Haum CC, MacEwen JD . The acute inhalation
toxicology of chlorine pentafluoride. Am Ind Hyg Assoc
WB, Gerarde HW . Oxygen difluoride (OF2). In: Toxicology
of drugs and chemicals. New York, NY: Academic Press,
Inc., p. 444.
HF Jr . Military and space short-term inhalation
standards. Arch Environ Health 12:488-490.
SUPPORT: LETTER FROM E I DUPONT DE NEMOURS & CO TO USEPA RE
PERFLUOROISOBUTYLENE DEGRADATION PRODUCT
OF TEFLON PEP FLUOROPOLYMER DURING MELT EXTRUSION W/ATTACHMENTS
CAS Registry Number: 382-21-8 (Perfluoroisobutylene)
Report Nos. NTIS/OTS0539061-1. EPA/OTS;
NTIS Report: INITIAL
SUBMISSION: PROGRESS REPORT ON TEFLON PYROLYSIS
PRODUCTS - INHALATION TOXICITY TESTS IN GUINEA PIGS WITH
COVER LETTER DATED 10-15-92. CAS Registry Number: 9002-84-0.
Report Nos. NTIS/OTS0571216.
EPA/OTS; Doc #88-920009560.
SUBMISSION: TOXICITY STUDIES OF PYROLYSIS
PRODUCTS OF FLUORINATED POLYMERS INCLUDING, PERFLUOROISOBUTYLENE,
HEXAFLUOROPROPYLENE, * WITH COVER LETTER DATED 10/15/92.
CAS Registry Numbers:
353-50-4 (Carbonyl fluoride, also known as Carbonyl difluoride)
Nos. NTIS/OTS0555698. EPA/OTS; Doc #88-920010279.
INITIAL SUBMISSION: TOXICITY STUDIES OF
PYROLYSIS PRODUCTS OF FLUORINATED POLYMERS (TEFLON POLYTETRAFLUOROETHYLENE)
WITH COVER LETTER DATED 10-15-92. HASKELL LABORATORY. CAS
353-50-4 (Carbonyl fluoride, also known as Carbonyl difluoride)
Nos. NTIS/OTS0571353. EPA/OTS; Doc #88-920009696.
STUDIES OF PYROLYSIS PRODUCTS OF FLUORINATED
Report Nos. NTIS/OTS0215306.
EPA/OTS; Doc #878220598.
REPORT ON TEFLON PYROLYSIS PRODUCTS
MR-220 INHALATION TOXICITY TESTS.
CAS Registry Numbers:
422-55-9 (Propane, 1-chloro-1,1,2,2,3,3-hexafluoro).
EPA/OTS; Doc #878220596.
Perfluoroisobutene (PFIB) is produced by
the pyrolysis, and as a by-product during the manufacture, of
polytetrafluoroethylene. When inhaled it produces a fulminating
and sometimes fatal pulmonary oedema similar to that of phosgene
after a latent peroid of 6-8 h. As part of a study to determine
the retained dose and the factors that control the amount retained,
this study has investigated the retention in rats of inhaled PFIB
at concentrations of 10, 50 and 250 mugl/-1 in a flow-through
system combining head-only exposure and plethysmography. Uptake
of PFIB was measured by gas chromatography during elevated and
reduced inspired volume and respiratory rate induced by exposure
to increased CO2 and injection of pentobartione, respectively.
The percentage of PFIB retained in the upper airways and lungs
was found to be 27.5, 28.1 and 23.7% of the amount inspired at
the three concentrations tested. The rate of uptake (nmol
min-1 kg-1) of PFIB was a power law of the amount inha [astract
Ref: Retention of inhaled perfluoroisobutene
in the rat. by MAIDMENT MP, UPSHALL DG. J APPL TOXICOL; 12 (6).
Fluoropolymers, especially polytetrafluoroethylene (PTFE), have
good fire-resistance properties, but their application is limited
by concerns over the toxicity of their thermal
decomposition products. In experiments using a tube furnace system
similar to the DIN 53 436 method, the 30-minute (+ 14 days observation)
LC50 im mass loss terms was found to be 2.9 mg l-1 (Standard Error
0.04) under non-flaming conditions, approximately ten times as
toxic as wood and most other materials. Toxicity was due to upper
respiratory tract and airway irritation, and was consistent with
the known effects of carbonyl fluoride
and hydrogen fluoride. When
decomposed in the NBS cup furnace test under non-flaming conditions,
PTFE evolved extreme-toxicity products with
an LC50 of approximately 0.05 mg l-1 (mass loss), approximately
1000 times as toxic as wood and most other materials. Toxicity
was due to deep lung irritation and oedema. Investigations
of the range of conditions under which the [abstract truncated]
Ref: Recent developments in understanding
the toxicity of PTFE thermal decomposition products. by PURSER
DA. FIRE MATER; 16 (2). 1992. 67-75.
The toxic effects of thermal degradation products of polytetrafluoroethylene
(9002-84-0) (PTFE) and tetrafluoroethylene (116-14-3) /
hexafluoropropylene (116-15-4) copolymer (FEP) were studied in
rats. Twenty two male Crl:CD-BR-rats were exposed to FEP pyrolysis
products in a National Bureau of Standards (NBS) exposure chamber
for 30 minutes; 4 rats were killed 1 to 4 hours after for microscopic
examination of lung and nasal sections and the remaining 18 were
observed for 24 hours post exposure. Four rats exposed to air
only were used as controls. Further experimentation involved exposure
of 14 rats to PTFE pyrolysis products in a low temperature decomposition
exposure system for 4 hours; again, some rats were killed 1 to
4 hours thereafter for microscopic evaluations and the remaining
rats were observed for 24 hours. Determinations
were made regarding the presence of gaseous hydrogen fluoride
and particle size. An intratracheal instillation experiment
was also conducted in which rats were exposed to 0.05 milligrams
aged PTFE particulate agglomerates
and their lungs were examined microscopically. In
the NBS chamber, the approximate lethal concentration (ALC) of
particulate generated was 0.3mg/m3 of FEP pyrolysis products;
in the second chamber, the ALC of fume evolved from PTFE was 0.1mg/m3.
Fresh particles, 0.02 to 0.15 micrometers, were thought to be
the toxic agents. In the inhalation studies, exposed rats
died from pulmonary congestion and edema but only minimal respiratory
epithelial damage was seen in the nasal cavity or airways.
Pulmonary lesions were characterized by
alveolar and interstitial edema and intraalveolar hemorrhage due
to damaged Type-I pneumocytes and were associated with alveolar
capillary neutrophilia. The authors recommended
investigation of the mode of action of PTFE particulates on Type-I
Ref: Pulmonary Response of Rats Exposed
to Polytetrafluoroethylene and Tetrafluoroethylene Hexafluoropropylene
Copolymer Fume and Isolated Particles. by Lee KP, Seidel WC. Inhalation
Toxicology, Vol. 3, No. 3, pages 237-264, 53 references, 1991.
on potential occupational hazards from exposure to carbonyl fluoride
(353-50-4) was reviewed. Topics discussed included chemical and
physical properties, production, use, manufacturers and distributors,
manufacturing processes, occupational exposure, and biological
effects. Potential exposure to carbonyl
fluoride occurs as a result of the thermal decomposition of polytetrafluoroethylene
(PTFE) in air. Effects of acute exposure in animal studies
included extreme malaise and weakness which
preceded death. Subchronic exposure studies with PTFE pyrolysis
products revealed pathologic changes in
the respiratory tracts and livers of exposed animals. Protein,
glucose, ketones, and occult blood appeared in the urine following
exposure. No information was available concerning chronic exposures,
carcinogenicity, mutagenicity, teratogenicity, or reproductive
1987. Information Profiles on Potential Occupational Hazards:
Carbonyl Fluoride. Second Draft. Syracuse Research Corp., NY.
Center for Chemical Hazard Assessment. Sponsored by National Inst.
for Occupational Safety and Health, Rockville, MD. Report No.
• FORMATION OF ACUTE
PULMONARY TOXICANTS FOLLOWING THERMAL DEGRADATION OF PERFLUORINATED
POLYMERS EVIDENCE FOR A CRITICAL ATMOSPHERIC REACTION.
by WILLIAMS SJ, BAKER BB,
LEE K-P. FOOD CHEM TOXICOL; 25 (2). 1987. 177-186. No
AND TOXICITY OF THERMAL DESTRUCTION PRODUCTS OF FLUORINE CONTAINING
SYNTHETIC MATERIALS. by PODDUBNAYA
LT, EITINGON AI, NAUMOVA LS, SHASHINA TA, KOROBEINIKOVA NN. GIG
SANIT; 0 (12). 1981.
CAS Registry Numbers:
7664-39-3 (Hydrofluoric acid)
630-08-0 (Carbon monoxide)
124-38-9 (Carbon Dioxide)
The relative toxicities of thermal degradation products from four
fluoropolymers were determined in rats. The polymers were polytetrafluoroethylene
(9002-84-0) (PTFE), copolymers of vinylidene fluoride (75-38-7)
and hexafluoropropene (116-15-4) with and without additives (VF2-A
and VF2/HFP), and the terpolymers of PTFE, VF2, and HFP (VF2/HFP/TFE).
Male Sprague-Dawley-rats were exposed for 30 minutes to the pyrolysis
products of VF2/HFP, VF2/HFP-A, and VF2/HFP/TFE at 550 and 800
degrees-C, and to the pyrolysis products of PTFE at 625 and 800
degrees-C. Survivors were killed at 1, 2, 4, 8, 16, and 32 days
postexposure and examined for pathological changes in organs and
tissues. Hydrolyzable fluoride concentrations were determined
for pyrolysis products of all polymers at both temperatures. At
550 degrees-C, the median lethal dose ranged from 1.06 grams (g)
VF2/HFP-A to 2.36g VF2/HFP. The median lethal
dose of PTFE at 625 degrees-C was 0.5g. At 800 degrees-C, the
median lethal dose ranged from 0.38g PTFE (for a 5 minute exposure)
to 0.59g VF2/HFP (for a 30 minute exposure). Initial pathological
response to pyrolysates included capillary damage leading to pulmonary
edema, and alveolar hypertrophy and
desquamation. For survivors, edema was resolved and a proliferative
phase began after 48 hours. Lungs returned to normal after 1 week.
No other organ system was involved. No relationship was found
between hydrolyzable fluoride concentrations of pyrolysates and
toxicities. The authors conclude that the
pyrolysis products of PTFE are more toxic than those of polymers
containing VF2 and HFP.
Ref: The Acute Inhalation Toxicity
in Rats from the Pyrolysis Products of Four Fluoropolymers. by
Carter VL Jr, Bafus DA, Warrington HP, Harris ES. Toxicology and
Applied Pharmacology, Vol. 30, No. 3, pages 369-376, 9 references,
Urinary fluoride levels were investigated as an index of polytetrafluoroethylene
(PTFE) exposure, since carbonyl fluoride,
a pyrolysis product of PTFE, is metabolized and excreted as inorganic
fluoride ion. Spot urine samples and occupational histories
relating to polyment fume fever were obtained from 77 workers
at a small PTFE fabricating plant. Environmental air samples for
PTFE were taken. Air levels of PTFE ranging from 0-5.48 mg/m-3
were found. All urine values fell below the level at which systemic
effects are reported to occur. Analysis
of variance demonstrated that the mean urinary fluoride level
among workers who had 1 or more years of exposure to PFTE who
also had experienced 1 or more reported episodes of polymer fume
fever was significantly higher (P< 0.01) than that among employees
with less than 1 yr or more of exposure and no history of polymer
fume fever. Additional exposure beyond 1 yr and additional
polymer fume fever episodes did not result in the further elevation
of urine fluoride levels.
Ref: Urinary fluoride levels in polytetrafluoroethylene
fabricators; POLAKOFF PL, BUSCH KA , OKAWA MT. AM IND HYG ASSOC
J; 35 (2). 1974 99-106.
Abstract: Environmental survey of the hazards arising from Teflon
(9002-84-0) dust and noise in a plastics industrial unit. Total
dust air concentration levels obtained from 23 persons and four
general area samples range from 0.0 to 5.5 milligrams per cubic
meter, as against the standard of 15 milligrams per cubic meter.
Recommendations include improved housekeeping program to keep
dust sources to a minimum, prohibition of smoking in areas where
Teflon is cut, machined, or processed, reduction of noise levels
to within standards of 90 decibels by instituting engineering
controls, establishment of a hearing conservation program including
audiometry, and use of personal protective devices. Symptoms of
Teflon fume fever are given with effects of smoking Teflon-contaminated
cigarettes, which include chills, nausea, vomiting, body and joint
pains, sweating, weakness, and dry cough. Polytetrafluoroethylene
is not considered damaging to skin when used at ordinary temperatures.
Above 400 degrees centigrade, perfluorisobutylene
and carbonyl fluoride (353504) are formed by the pyrolysis of
Ref: Health Hazard Evaluation Report
HHE-72-29-28, Modern Industrial Plastics Division, Duriron Company,
Dayton, Ohio. by Okawa MT, Polakoff PL. Hazard Evaluation
Services Branch, NIOSH, Cincinnati,
Ohio, Report No. HHE-72-29-28, 28 pages, 12 references, 1973.
Abstract: A literature survey relating to the processes occurring
in the decomposition of polyfluoroethylene
(9002-84-0) resins, depending upon the heating temperature,
and toxicological data, is presented. The work conditions during
the thermal treatment of polyfluoroethylene resins were studied
by taking samples of objects baked in closed door ovens at temperatures
of from 375 to 415 degrees C. It was determined
that the atmosphere can be polluted with such compounds as perfluoroisobutylene,
tetrafluoroethylene (116-14-3), oxyfluorides (7783-41-7), hydrogen
fluoride, carbon-monoxide (630080), and polymer aerosols.
The implementation of preventive measures, such as: 1) isolating
the ovens from other work sections; 2) constructing block exhaust
ventilations from the heating ovens; 3) hermetically sealing the
oven doors; 4) constructing exhaust vents tightly adhering to
the upper oven walls; and 5) daily controls of the atmosphere,
permitted the reduction of toxic pollutants in the atmosphere.
It is concluded that the thermal processing of polyfluoroethylene
resins required the special attention of hygienists and engineering
personnel. (Russian: English translation available)
Ref: Fundamental Problems of Industrial
Hygiene in the Processing of Polyfluoroethylene Resins. Marchenko
FM. Gigiena Truda i Professional'nye Zabolevaniia, Vol. 10, No.
11, pages 12-18, 9 references, 1968.
Abstract: Thirty payroll and eight staff employees of a polytetrafluoroethylene
(9002-84-0) (PTFE) manufacturing plant were interviewed and the
plant investigated to determine the cause of polymer fume fever
in plant employees. Fourteen of the 30 payroll employees
had experienced symptoms of the fever in the two months previous
to the interview. Thirty-two incidents of polymer fume fever were
reported by these 14 workers. Only employees working in the finishing
room, where PTFE was dried, sifted, and packed, had been affected.
Of the 18 men who worked in the finishing room, 12 who were smokers
accounted for 30 incidents. Six of the workers who rolled their
own cigarettes had incurred 21 of these 30 attacks. Of the eight
staff employees, only one, a pipe smoker, had experienced an attack
of polymer fume fever. Air samples were taken in the finishing
room at points close to the drying ovens and the ovens where the
polymer was further heated when required. When PTFE was heated
to normal drying temperatures, hydrochloric acid (7647010) was
occasionally detected in concentrations up to 35ppm. Hydrogen
fluoride (7664-39-3), in concentrations no greater than 6ppm,
was detected when the temperature was increased beyond 300 degrees-C.
The results indicate that the majority of incidents of
polymer fume fever resulted from the smoking of PTFE contaminated
tobacco. Precautionary measures, designed to prevent further incidents
of polymer fume fever, were recommended.
Ref: Polymer Fume Fever Due to Inhalation
of Fumes from Polytetrafluoroethylene. by Adams WGF. Transactions
of the Association of Industrial Medical Officers, Vol. 13, pages
20-21, 4 references, 1963.
Abstract: Guidelines for the safe handling and use of "Teflon"
fluorocarbon resins, specifically polytetrafluorethylene
(9002-84-0) (PTFE) and fluorinated-ethylene-propylene (FEP)
polymers manufactured by the DuPont Company, are given. Although
no hygienic standard for PTFE and FEP dusts has been set, a maximum
atmospheric concentration of 15mg/cubic meter may be tolerated
over an 8 hour period on a nuisance basis without significant
hazard, since the oral and inhalation toxicities of the undecomposed
polymers are practically nil. Decomposition
products appear only at temperatures above 200 degrees-C. No practical
way has yet been devised to express safe concentrations of the
various possible mixtures of the decomposition products, which
include tetrafluoroethylene (116-14-3), hexafluoropropylene (116-15-4),
octafluoroisobutylene, and hydrogen fluoride (7664-39-3).
Above 250 degrees-C, toxicologically significant amounts of these
products are evolved and polymer fume fever
may result from exposure to them or from smoking Teflon contaminated
cigarettes. The decomposition products become flammable
above 690 degrees-C. The general physical and chemical properties
of the two resins are presented, but there are no identifying
characteristics of taste, odor or irritation. Based on results
reported from both animal and human toxicity studies, recommendations
are given for monitoring the atmosphere for fluorine (7782-41-4)
containing gases, for minimizing worker exposure during
operations generating high temperatures (including machining Teflon
parts, smoking, and fire fighting),
and for first aid procedures.
Ref: "Teflon" Fluorocarbon Resins
and Their Decomposition Products. Anonymous. American Industrial
Hygiene Association Journal, Vol. 24, pages 198-200, 8 references,
by the du Pont Company investigating the toxicity
of pyrolysis products of two tetrafluoroethylene (TFE) resins,
Teflon-1 and Teflon-6 (9002-84-0)
are reviewed. TFE resins are physiologically inert, but when subjected
to temperatures of 300 degrees-C and above, toxic effects in rats
are observed. In addition to causing death
of experimental animals, toxic symptoms include pulmonary congestion
and edema, bronchitis, bronchopneumonia, chronic pneumonia, and
emphysema. As temperature
increases above 300 degrees-C, the rate of thermal decomposition
increases and the pyrolysis products change.
Small quantities of carbon dioxide and fluorides that do
not appear to be important toxicologically are evolved when TFE
resins are exposed to temperatures from 300 to 350 degrees-C.
However, a fine particulate material evolving
during pyrolysis is toxic to rats. The observed toxicity of pyrolysis
products heated to 380 degrees-C and above may be due chiefly
to octafluoroisobutylene [also known as Perfluoroisobutylene]
(382-21-8). The relative toxicity
of pyrolysis products of Teflon-1 and Teflon-6 corresponds to
the amount of matter evolved. Filtration of the pyrolysis stream
significantly reduces the toxicity of the products evolved at
temperatures of 325 and 350 degrees-C. New
manufacturing techniques for TFE resins have resulted in products
with improved thermal stability and corresponding lower toxicity
of pyrolysis products. The authors conclude that experimental
work is still needed to allow exact characterization of the toxic
pyrolysis products of TFE resins.
Ref: The Toxicity of the Pyrolysis Products
of "Teflon" TFE-Fluorocarbon Resins. Clayton JW Jr,
Hood DB, Raynsford GE. Haskell Laboratory for Toxicology and Industrial
Medicine, E. I. du Pont de Nemours and Co., Inc., Wilmington,
Delaware, Presented at the American Industrial Hygiene Association
Annual Meeting, 9 pages, 1959.
Abstract: Teflon (9002-84-0) vapor toxicity under various thermal
conditions is reviewed. It is noted that under normal usage conditions
Teflon is among the most inert, nontoxic, and nonflammable substances
tested. The primary uses of Teflon are described. Its nontoxic
nature has been proven by animals tests. At 200 degrees-C or higher
Teflon decomposes to release toxic fumes which cause polymer fume
fever in humans. The incidence of this reaction among Teflon workers
is discussed and the symptoms described. It is noted that the
effects last for 1 to 2 hours but rarely longer, and recovery
is complete within 24 to 36 hours. The rate of decomposition of
Teflon resins at various temperatures ranging from 200 to 500
degrees is described and the products of pyrolysis at these temperatures
are specified. The major component of pyrolysis
at 400 degrees is the monomer tetrafluoroethylene (116-14-3)
a relatively innocuous gas which comprises at least 95 to 97 percent
of the gaseous output and hexafluoropropylene
(116-15-4) (2 to 3 percent). Trace
amounts of hydrogen fluoride (7664393) have also been detected
especially in the presence of moisture during Teflon pyrolysis,
as well as perfluoroisobutylene (382-21-8).
The toxicity of the latter two compounds
in animals is discussed. The toxic response in animals
is reviewed in terms of human maximal allowable concentrations.
Other features of the pyrolytic decomposition
of Teflon such as weight loss at various temperatures is tabulated.
Control measures for storage of Teflon and other fluorocarbon
plastics, fabrication, installation and maintenance of components
utilizing Teflon and disposal of scrap Teflon are discussed as
well as personal hygiene, ventilation during heating of Teflon,
use of emergency personal protective equipment, and maintenance
of adequate medical records.
Ref: Environmental And Occupational
Health Information Letter Number 13A. Toxicity Of Products Of
Thermal Decomposition Of Teflon. Anonymous. Office of the Surgeon,
Air Material Command, Wright-Patterson Air Force Base, Ohio, 7
pages, 9 references, 1958.
Abstract: The effects of various gaseous atmospheres on the thermal
decomposition of polytetrafluoroethylene
(9002-84-0) were investigated. The rate of degradation
was measured by determining the weight loss of 1 gram of the polymer
after periodic heating to between 450 and 500 degrees-C in the
presence of various flowing gases. Gases studied including those
exhibiting a strong catalytic effect on the rate of degradation,
such as oxygen (7782447) (O2), nitrous-oxide (10024972), hydrogen-sulfide
(7783064), and sulfur-dioxide (7446095); those producing an initial
inhibitory effect, as hydrogen (1333740) (H2), chlorine (7782505),
carbon-tetrachloride (56235), and toluene (108883); and those
that showed neither effect, nitrogen (7727379), and benzotrifluoride
(98-08-8). Gaseous products were characterized and quantitated.
With O2, the major product was carbon-dioxide
(124389) (CO2); perfluoroethylene
(116-14-3), silicon tetrafluoride (7783-61-1),
and CO2 in equivalent amounts were the major products of H2; with
toluene the major product was perfluoroethylene. Those
gases giving catalytic effects did so by increasing transfer mechanisms
or defluorination. Those showing inhibition effects gave
kinetic curves with inflection points, and there was a change
in the mechanism as noted by the product distribution. The authors
conclude that although the inhibited reactions produce few monomers
and are highly random, there are relatively
high rates of induced decomposition.
Ref: Thermal Decomposition of Polytetrafluoroethylene
in Various Gaseous Atmospheres. Wall LA, Michaelsen J. Journal
of Research of the National Bureau of Standards, Vol. 56, No.
1, pages 27-34, 12 references, 1956.
Abstract: The necessity of conducting thermochemical studies
on fluorocarbons is discussed in light of the growing industrial
importance of such compounds, and because relatively little information
was previously available about heats of formation and other properties.
Measurements were therefore made of the heat evolved in: 1) the
explosive decomposition of tetrafluoroethylene (116-14-3) (TFE);
2) the explosive hydrogenation of TFE; and 3) the formation of
two kinds of combustion products from TFE. The combustion reactions
are general and were applied to TFE, hexafluoropropylene (116154),
octafluorocyclobutane (115-25-3), and Teflon
(9002-84-0) or polytetrafluoroethylene (9002-84-0) (PTFE).
By combining the results of these measurements with established
values for hydrogen fluoride (7664-39-3) and carbon-dioxide ,
the heats of formation of all the compounds involved in the reactions
were obtained and compared with other values reported in the literature.
In particular, the values obtained for carbon tetrafluoride (75-73-0),
212.7kcal, and for TFE, 151.3kcal, are lower than those reported
by other investigators, but the value for the polymer PTFE, 199.9kcal,
is higher. The experimental details regarding apparatus, materials,
and procedures used are presented in full, and heats of formation
are arranged in tabular form.
Ref: Thermochemical Studies on Fluorocarbons:
Heat of Formation of CF4, C2F4, C3F6, C2F4 Dimer, and C2F4 Polymer.
Duus HC. Industrial and Engineering Chemistry, Vol. 47, No. 7,
pages 1445-1449, 12 references, 1955.
Abstract: The mechanism of thermal breakdown of teflon (9002-84-0)
and related fluoropolymers as obtained by S. L. Madorsky and associates
at the National Bureau of Standards is described. A pyrolysis
method was used involving thermal decomposition of a sample and
subsequent distillation under such a high vacuum that there was
no return of escaping molecules to the evaporating surface. Under
these conditions, the fragments into which the polymeric chain
is decomposed by heat could be collected without further fragmentation
due to molecular collision. To obtain the activation energy of
the polymers (a measure of the ease of decomposition), it was
necessary to determine the rate of volatilization from each polymer
sample over a suitable temperature range by measuring the weight
loss in vacuum. In the case of Teflon, which
yields mostly monomer breakdown products from the chain ends,
pressure measurements of the volatiles produced in a fixed volume
could also be used for the same purpose. Substitution of one or
more hydrogen (1333740) atoms for fluorine (7182414) on the chain
changes radically the polymer and its mechanism of breakdown.
In the order of decreasing stability, as indicated by their temperature
threshold for appreciable decomposition, the polymers
tested are: Teflon, at 490 degrees-C; polyvinylidene fluoride,
at 430 degrees-C; and polyvinyl fluoride and polytrifluoroethylene
below 400 degrees-C. The latter two yield large amounts of long
chain molecular fragments on heating, whereas polyvinylidene
fluoride gives off a relatively larger percent of hydrogen fluoride
Ref: Thermal Stability of Teflon. Anonymous. National Bureau of
Standards, Technical News Bulletin, Vol. 38 No. 3, pages 43-45,
7 references, 1954.
(9002-84-0), a polymeric material possessing good heat stability
and chemical inertness, was pyrolytically cracked at temperatures
ranging from 600 to 700 degrees-C and at pressures between 5 and
760mm and the thermal degradation products were isolated using
the Podbielniak distillation method. The products of thermal
cracking were of low molecular weight and consisted of C2F4, which
was identified as tetrafluoroethylene (116-14-3);
C4F8, identified as octafluorocyclobutane; and C3F6, which was
not identified during the study. These three compounds were formed
in varying amounts depending on the experimental conditions. Tetrafluoroethylene
was formed in increasing amounts as the pressure was decreased
and was the sole product as very low pressures. At higher pressures,
the yield of tetrafluoroethylene decreased, and C3F6 and octafluorocyclobutane
were formed in increasing proportions. Increasing the temperature
from 600 to 700 degrees-C had only a minor effect on the composition
of the thermal degradation products. Results suggest:
1) that the original polymer (polytetrafluoroethylene) decomposes
by splitting off units of the basic monomer (tetrafluoroethylene)
from a degrading fragment, and
2) that these monomer units are capable of undergoing secondary
reactions, favored by increased pressure, to form compounds of
higher molecular weight. A mechanism consistent with this explanation
Very few carbon (7440440) to fluorine (7782414) bonds appear to
be broken by direct attack of an active fragment.
Ref: Pyrolysis of Polytetrafluoroethylene.
Lewis EE, Naylor MA. Journal of the American Chemical Society,
Vol. 69, pages 1968-1970, 14 references, 1947.