IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
Health and Safety Guide No. 106
PHOSGENE
HEALTH AND SAFETY GUIDE
UNITED NATIONS ENVIRONMENT PROGRAMME
INTERNATIONAL LABOUR ORGANISATION
WORLD HEALTH ORGANIZATION
WORLD HEALTH ORGANIZATION, GENEVA 1998
IPCS
Health and Safety Guide No. 106
PHOSGENE
HEALTH AND SAFETY GUIDE
This is a companion volume to
Environmental Health Criteria 193: Phosgene
Published by the World Health Organization for the International
Programme on Chemical Safety (a collaborative programme of the United
Nations Environment Programme, the International Labour Organisation,
and the World Health Organization) and produced within the framework
of the Inter-Organization Programme for the Sound Management of
Chemicals
WORLD HEALTH ORGANIZATION, GENEVA 1998
This is a companion volume to Environmental Health Criteria : Phosgene
Published by the World Health Organization for the International
Programme on Chemical Safety (a collaborative programme of the United
Nations Environment Programme, the International Labour Organisation,
and the World Health Organization)
This report contains the collective views of an international group of
experts and does not necessarily represent the decisions or the stated
policy of the United Nations Environment Programme, the International
Labour Organisation, or the World Health Organization
WHO Library Cataloguing in Publication Data
Health and safety guide for Phosgene
(Health and safety guide ; no. 106)
1.Phosgene - toxicity 2.Environmental exposure
3.Guidelines I.International Programme on Chemical Safety
II.Series
ISBN 92 4 15106 0 (NLM Classification: QV 664)
ISSN 0259-7268
The World Health Organization welcomes requests for permission to
reproduce or translate its publications, in part or in full.
Applications and enquiries should be addressed to the Office of
Publications, World Health Organization, Geneva, Switzerland, which
will be glad to provide the latest information on any changes made to
the text, plans for new editions, and reprints and translations
already available.
(c) World Health Organization 1998
Publications of the World Health Organization enjoy copyright
protection in accordance with the provisions of Protocol 2 of the
Universal Copyright Convention. All rights reserved.
The designations employed and the presentation of the material in this
publication do not imply the expression of any opinion whatsoever on
the part of the Secretariat of the World Health Organization
concerning the legal status of any country, territory, city or area or
of its authorities, or concerning the delimitation of its frontiers or
boundaries.
The mention of specific companies or of certain manufacturers'
products does not imply that they are endorsed or recommended by the
World Health Organization in preference to others of a similar nature
that are not mentioned. Errors and omissions excepted, the names of
proprietary products are distinguished by initial capital letters.
CONTENTS
INTRODUCTION
1. PRODUCT IDENTITY AND USES
1.1. Identity
1.2. Physical and chemical properties
1.3. Conversion factors
1.4. Analytical methods
1.5. Production, uses and occurrence
2. SUMMARY AND EVALUATION
2.1. Exposure
2.2. Environmental fate
2.3. Kinetics and metabolism
2.4. Effects on organisms in the environment
2.5. Effects on animals and in vitro test systems
2.6. Effects on humans
3. CONCLUSIONS
3.1. Human health
3.2. Environment
4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY
RESPONSE
4.1. Human health hazards, prevention and protection, first aid
4.1.1. Advice to physicians
4.1.1.1 Symptoms of poisoning
4.1.1.2 Medical treatment
4.1.2. Health surveillance advice
4.2. Explosion and fire hazards
4.3. Storage
4.4. Transport
4.5. Spillage and disposal
4.5.1. Spillage
4.5.2. Disposal
4.6. Other protective measures
5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION
6. SUMMARY OF CHEMICAL SAFETY INFORMATION
7. CURRENT REGULATIONS, GUIDELINES AND STANDARDS
7.1. Occupational exposure limit values
7.2. Labelling, packaging and transport
BIBLIOGRAPHY
INTRODUCTION
The Environmental Health Criteria (EHC) monographs produced by the
International Programme on Chemical Safety include an assessment of
the effects on the environment and on human health of exposure to a
chemical or combination of chemicals, or physical or biological
agents. They also provide guidelines for setting exposure limits.
The purpose of a Health and Safety Guide is to facilitate the
application of these guidelines in national chemical safety
programmes. The first three sections of a Health and Safety Guide
highlight the relevant technical information in the corresponding EHC.
Section 4 includes advice on preventive and protective measures and
emergency action; health workers should be thoroughly familiar with
the medical information to ensure that they can act efficiently in an
emergency. Within the Guide is a Summary of Chemical Safety
Information which should be readily available, and should be clearly
explained, to all who could come into contact with the chemical. The
section on regulatory information has been extracted from the legal
file of the International Register of Potentially Toxic Chemicals
(IRPTC) and from other United Nations sources.
The target readership includes occupational health services, those in
ministries, governmental agencies, industry, and trade unions who are
involved in the safe use of chemicals and the avoidance of
environmental health hazards, and those wanting more information on
this topic. An attempt has been made to use only terms that will be
familiar to the intended user. However, sections 1 and 2 inevitably
contain some technical terms. A bibliography has been included for
readers who require further background information.
Revision of the information in this Guide will take place in due
course, and the eventual aim is to use standardized terminology.
Comments on any difficulties encountered in using the Guide would be
very helpful and should be addressed to:
The Director
International Programme on Chemical Safety
World Health Organization
1211 Geneva 27
Switzerland
THE INFORMATION IN THIS GUIDE SHOULD BE CONSIDERED AS A STARTING
POINT TO A COMPREHENSIVE HEALTH AND SAFETY PROGRAMME
1. PRODUCT IDENTITY AND USES
1.1 Identity
Common name:
Phosgene
Common synonyms: carbonyl chloride, carbonic acid dichloride,
carbon oxychloride, chloroformyl chloride
Molecular formula:
COC12
Chemical structure:
Cl
\
C = O
/
Cl
IUPAC name:
carbonic dichloride
CAS name:
carbonic dichloride
CAS registry number: 75-44-5
RTECS registry number: SY 5600000
UN transport number: UN 1076
Technical grade phosgene has a purity between 95 and 99%
depending upon the intended local use. Impurities include nitrogen,
carbon monoxide, hydrochloric acid, free chlorine and sulfur
compounds.
1.2 Physical and chemical properties
Phosgene is a colourless gas at room temperature and standard
pressure. It has a suffocating odour similar to mouldy hay. Although
the odour of phosgene can be perceived at 1.6 mg/m3 (0.4 ppm), after
adaption recognition will be at levels >6 mg/m3 (1.5 ppm). It is
slightly soluble in water and freely soluble in most liquid
hydrocarbons, benzene, toluene and glacial acetic acid.
In water, phosgene is sparingly soluble and decomposes to
hydrochloric acid and carbon dioxide. It also reacts with ethanol but
is soluble unaltered in benzene, toluene, most liquid hydrocarbons,
and in glacial acetic acid.
Phosgene decomposes on heating above 300 °C producing chlorine
and carbon monoxide. It is formed by thermal decomposition of
chlorinated solvents, e.g., chloroform, carbon tetrachloride, tri- and
tetra-chloroethylene and methylene chloride, as well as by the thermal
degradation of chlorinated polymers. Some of its physical properties
are as follows:
Melting point (°C) -127.8
Boiling point (°C) 7.56
Relative density (water = 1) 1.4
Relative vapour density (air = 1) 3.42
Vapour pressure (20 °C) 161.6 kPa
1.3 Conversion factors
1 ppm = 4.05 mg phosgene/m3 air
1 mg phosgene/m3 = 0.25 ppm
at 25 °C and 101.3 kPa
1.4 Analytical methods
Phosgene in air may be detected by ultraviolet spectrophotometry,
gas chromatography, infrared spectrophotometry, automated colorimetry
and paper tape monitors containing 4-(4-nitrobenzyl)-pyridine and
n-benzylaniline, both for personal badges and in continuous
monitoring. Monitoring methods should provide data on accumulated
exposure levels over time, preferably on a continuous basis.
1.5 Production, uses and occurrence
Phosgene is produced by reacting equimolar amounts of carbon
monoxide and anhydrous chlorine in the presence of a carbon catalyst
under appropriate conditions of temperature and pressure. The great
majority is used directly in closed systems on-site.
Phosgene is used as an intermediate in the manufacture of many
organic chemicals. The largest amount (approximately 80% of world
production) is used to produce toluene diisocyanate and other
isocyanates used in polyurethane foam production, preparation of
plastics, and pesticides. Accurate production figures are hard to
determine since over 99% of phosgene production is "used on site".
Approximately 3×106 tonnes of phosgene are used annually worldwide.
Phosgene levels in ambient air can arise from the thermal and
photo-degradation of chlorinated solvents and chlorinated polymers.
The major source of phosgene is the photochemical oxidation of
chloroethylenes such as tri- and tetra-chloroethylene. Accidental
releases from industries will affect only areas around the plant and
not usually the general environment.
2. SUMMARY AND EVALUATION
2.1 Exposure
Human exposure to phosgene is by inhalation. Potential sources
of exposure include the production and use of phosgene, ambient air
and from the photo and thermal degradation of chlorinated solvents and
polymers.
Although few data are available, average ambient air values vary
between 80 and 130 ng/m3. The total daily intake would thus be
between 1.6 and 2.6 µg. Much higher levels of phosgene exposure are
possible during the home use of chlorinated solvents, e.g., methylene
chloride, under conditions where temperatures are sufficiently high to
lead to thermal degradation.
Data are inadequate to determine quantitatively the exposure to
phosgene in the workplace. However, those working simultaneously with
flames and/or thermal energy sources and organochlorine solvents or
chlorinated polymers can be exposed to phosgene levels well above the
present threshold limit value (time-weighted average) of 0.4 mg/m3
(0.1 ppm).
Fire-fighters and workers engaged in welding and the building
trade are at risk from levels of phosgene formed by the thermal
degradation of chlorinated solvents and polymers. Accidental release
of phosgene during its manufacture, use or transport can lead to high
levels of exposure in workers and in the general population in the
vicinity of the accident.
2.2 Environmental fate
At normal ambient temperatures, the major pathway for phosgene
degradation in air is gas-phase hydrolysis. However, even at high
levels of humidity, phosgene in air is only slowly degraded and is
likely to be persistent in the atmosphere and subject to long-range
transport.
In water, phosgene is rapidly degraded to hydrochloric acid and
carbon dioxide.
Detectable levels of phosgene in soil and vegetation are unlikely
due to heterogeneous abiotic degradation.
2.3 Kinetics and metabolism
There are very few data on the absorption, metabolism,
distribution and fate of phosgene. Exposure is by inhalation. In
view of the extremely short half-life (0.026 seconds) in aqueous
solutions, and the penetration into the tissues of the respiratory
tract by phosgene gas, only minimal amounts of phosgene are
distributed in the body and no significant retention of phosgene in
the body is possible. The hydrolytic products of phosgene,
hydrochloric acid and carbon dioxide, are disposed by the body through
normal physiological processes.
Phosgene exerts its toxicity through the acylation of proteins as
well as through the release of hydrochloric acid. The amino, hydroxyl
and sulfhydryl groups in proteins appear to be the target for
acylation, leading to marked inhibition of several enzymes related to
energy metabolism and a breakdown of the blood:air barrier.
2.4 Effects on organisms in the environment
No information has been reported on the effects of phosgene on
the environment. However, the levels of phosgene now found in the
general environment would not be expected to result in significant
effects to aquatic or terrestrial biota.
Damage to plants and aquatic organisms could occur in areas where
accidental release of phosgene has occurred, owing to the rapid
release of hydrochloric acid.
2.5 Effects on animals and in vitro test systems
In all species that have been studied, the lung is the major
target organ. After acute exposures of between 4 and 800 mg/m3
(1-200 ppm) the toxicological effect is due to the exposure
(C) x time (T) (Habers Law), based on studies of lung disease and
death. This relationship does not hold for chronic exposures.
The L(CT)50 for single exposure was reported to vary widely
among animal species, ranging from 900 mg/m3-min (225 ppm-min) in the
mouse to 1920 mg/m3-min (250 ppm-min) in the monkey. In all species
the characteristic pathological feature was the dose-dependent
clinical manifestation of pulmonary oedema. The extent of the
long-term chronic effects of acute exposure appears to depend on the
severity of the initial pathology. At low concentrations,
pathological changes in the terminal bronchioles and alveoli were
reported to be typical of a pulmonary irritant, whereas at higher
levels pulmonary oedema occurred, leading to interference with gas
exchange and death.
Preliminary data from single 4-h exposures to 2 or 4 mg/m3 in
rats and mice (480 mg/m3-min or 960 mg/m3-min) indicated a decrease
in pulmonary immunocompetence. No effects were seen at 0.4 mg/m3
(96 mg/m3-min). Although limited, other data confirmed these
findings. In rats exposed to 4 mg/m3 for 4 h (960 mg/m3-min), a
10-fold increase in influenza virus titre was noted per day
post-infection. Pulmonary bacterial clearance was reduced in rats
exposed for 6 h to 0.4 mg phosgene/m3 (144 mg/m3-min) or to
0.4 mg/m3 for 6 h/day, 5 days/week for 4 to 12 weeks. This effect
was reversible following termination of exposure. In a host
resistance assay in mice, exposure to concentrations of phosgene of
0.1 mg/m3 or more for 4 h (>24 mg/m3-min) led to an increase in
mortality from Streptococcus zooepidemicus infection.
No long-term exposure studies of phosgene have been reported and
studies in dogs exposed 1-3 times/week for 12 weeks are of limited
value for risk assessment in view of study design and a lack of dose
response. Furthermore, available data in experimental animals are
inadequate for the assessment of the potential reproductive,
developmental, neurotoxic and carcinogenic effects from phosgene
exposures.
Phosgene exposure can result in eye and skin irritation.
2.6 Effects on humans
As in experimental animals, the target organ in humans is the
lung. After acute exposure to between 4 and 800 mg/m3, Habers Law
(CxT) is applicable. The cascade of events after acute inhalation
exposure in humans is similar to that in experimental animals. Their
occurrence is dose-related and results in pulmonary oedema and death
in humans at levels exceeding 120 mg/m3-min. Three distinct
clinico-pathological phases can be recognized, namely: pain in the
eyes and throat and tightness of the chest, often with shortness of
breath, wheezing and coughing; a latent phase which is often
asymptomatic and lasts normally up to 24 h depending upon the
concentration and duration of exposure; and the final phase of
pulmonary oedema. In one study pulmonary oedema occurred after a
latent phase of 48 h.
Populations exposed to phosgene after industrial accidents have
reported a wide variety of symptoms, including headache, nausea,
cough, dyspnoea, fatigue, pharyngeal pain, chest tightness and pain,
intense pain in the eye, and severe lacrimation. After short-term
exposures throat irritation occurs at levels of 12 mg/m3 and eye
irritation is noted at 16 mg/m3. It has been calculated that doses
below 100 mg/m3 will result in no permanent adverse effects, whereas
pulmonary oedema results from doses above 600 mg/m3-min. Death has
been recorded at doses above 400 mg/m3-min, and exposure for several
hours at concentrations at or below the odour threshold of 6 mg/m3
may result in severe tissue damage and death. Thus, the odour
threshold for phosgene is an unacceptable parameter for early warning.
A review of the health status of workers recovering from acute
phosgene exposures has shown no adverse effects, but full recovery may
take several months.
Available data on human health effects associated with chronic
exposure to phosgene are extremely limited. Epidemiological studies
of phosgene production workers and uranium workers reported no adverse
effects on human health. However these investigations were limited by
small numbers of exposed workers, lack of reliable quantitative
information on exposure to phosgene, concomitant exposure to other
substances, limited number of end-points examined and limited
reporting of relevant information.
3. CONCLUSIONS
3.1 Human health
Phosgene is an extremely reactive chemical. It has the potential
to cause adverse effects in humans, the primary target organ being the
respiratory system.
Acute severe phosgene exposure primarily causes respira-tory
disease (pulmonary oedema) and may result in death. Survivors may
recover completely provided they receive proper medical support.
Accidental industrial releases can cause health problems to
workers and the nearby community.
Occupational exposures in closed-system industrial facilities
manufacturing and/or using phosgene and having good industrial hygiene
practices have not shown demonstrable risk to the workers.
Present levels of exposure to phosgene in the general population
are extremely low (1.6 to 2.6 µg/24 h) and do not pose a health risk.
However, individuals working with chlorinated solvents such as tri-
and tetrachloro-ethylene and methylene chloride or who are exposed to
chlorinated hydro-carbon polymers (e.g., polyvinyl chloride) in
contact with flames and/or other thermal energy sources, e.g.,
firemen, welders, painters and people working at home with these
materials, can be exposed to levels of phosgene known to cause adverse
effects in humans.
No human or animal data are available on the effects of chronic
low-level exposure to phosgene.
Available data are inadequate to derive a meaningful health-based
guidance value for exposure of the general population to phosgene.
However, recent toxicological studies in rats sub-chronically exposed
by inhalation to low levels of phosgene (0.4 mg/m3) indicate that
early pulmonary effects may occur at present threshold limit values.
Therefore, consideration by appropriate authorities might be given to
re-evaluating current occupational exposure guidelines for this
chemical.
3.2 Environment
No data are available concerning adverse effects of phosgene on
the ecosystem. However, levels of phosgene in the environment would
not be expected to result in significant effects on aquatic or
terrestrial biota. Owing to the very rapid release of hydrochloric
acid, damage to plants and aquatic organisms could occur in areas
where accidental release of phosgene occurs.
4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY
RESPONSE
4.1 Human health hazards, prevention and protection, first aid
The only organs affected are skin, lung and eyes, with the lung
being the primary target. Only a small portion of inhaled phosgene is
hydrolysed in the fluid films of the eyes and the upper respiratory
passages, giving rise to immediate but transient irritative signs and
symptoms, if the inhaled phosgene concentration is greater than
16 mg/m3 (4 ppm). Exposure to concentrations greater than
600 mg/m3-min (150 ppm-min) will cause pulmonary oedema, the clinical
signs and symptoms of which may need several hours to appear and will
do so in a dose-dependent fashion ("clinically latent period").
The human health hazards associated with certain types of
exposures to phosgene, together with preventive and protective
measures and first aid advice, are listed in the Summary of Chemical
Safety Information in section 6.
4.1.1 Advice to physicians
4.1.1.1 Symptoms of poisoning
Phosgene is an extremely strong respiratory tract irritant.
Alveolar toxic oedema may become evident 1 to 24 h after exposure
depending upon the level and duration of exposure. Signs and symptoms
of this type of pulmonary oedema are rapid shallow breathing,
shortness of breath, cough with production of frothy fluid, pulmonary
shadows on the X-ray, and reduction in vital capacity and respiratory
volume.
Eye and skin irritation occurs after severe exposure
(> 12 mg/m3). Serious skin injury from such exposures is unlikely.
Dermal burns can develop after exposure to the liquidified
material.
4.1.1.2 Medical treatment
Immediate termination of exposure is essential and the patient
should be removed to fresh air.
After exposure to liquid phosgene, contaminated clothing should
be removed and disposed of. Exposed skin should be washed with large
amounts of soap and water. If there was eye contact, the eyes should
be flushed with copious amounts of water for at least 15 min.
After exposure by inhalation, physical exertion should be avoided
and strict bed rest enforced for between 24 and 72 h, particularly if
the exposure dose was unknown or above 100 mg/m3-min (25 ppm-min).
Chest radiographs, arterial blood gases and other diagnostic
procedures are indicated to evaluate the presence of pulmonary oedema,
the primary danger after inhalation exposure to phosgene. When
pulmonary oedema is present the patient should be managed as though
respiratory failure was impending. Deep breathing is recommended to
remove additional phosgene from the lung.
No specific antidote is known. Hexamethylenetetramine is
effective only if administered prior to phosgene inhalation.
Pulmonary oedema should be managed with positive pressure oxygen
ventilation and the early intravenous administration of steroids
(e.g., 1 g of methyl-prednisolone) may be beneficial. Additionally,
the administration of such œ-adrenergic agonists as terbutaline,
albuteral, isoetharine and metaproterenol (as aerosols or nebulizers)
seems to be effective to correct bronchospasms. In severe cases
aminophylline should be considered to control bronchoconstriction and
relieve vasoconstriction. Most other drugs are ineffective and may
even be harmful, e.g., atropine, epinephrine, cardiac glycosides,
sedatives and expectorants. Antibiotic treatment might become
necessary if secondary infectious pneumonitis occurs.
Symptomatic therapy may become necessary, and patients should be
followed and surveyed until pulmonary function has normalized and the
patient fully recovered. Depending upon the exposure concentration
and time, full recovery can take several months.
4.1.2 Health surveillance advice
Workers having the potential for exposure to phosgene should be
supplied with personal monitors. Workplace controls should be
initiated to lower the levels of phosgene to levels not detectable by
paper strip monitors (about 0.4 to 0.5 mg/m3). Preferably,
monitoring devices must sound an alarm or otherwise warn workers when
a concentration of 0.8 mg/m3 is reached.
Preplacement and periodic medical examinations should be given to
all workers with the potential to be exposed to phosgene. These
should include chest radiographs and pulmonary function tests.
4.2 Explosion and fire hazards
Phosgene is non-flammable. However, the presence of water or
high temperature can cause containers of phosgene to rupture. This
can release both liquid and gaseous phosgene, as well as toxic thermal
degradation and reaction products such as hydrochloric acid, chlorine
and carbon monoxide.
All phosgene-containing vessels should be removed from the
vicinity of a fire, if this can be done without risk, and kept below
50 °C by water cooling unless phosgene is leaking from a cylinder.
Do not allow water to enter the containers. Fire-fighters must wear
protective clothing and a self-contained breathing apparatus. For
small fires use dry chemical or carbon dioxide. Use water spray, fog
or foam for larger fires.
4.3 Storage
Phosgene should be stored in appropriately labelled corrosion-
resistant steel cylinders that conform to rigid safety-design
specifications for this chemical. Storage should be in cool, dry, and
well-ventilated fire-proof rooms isolated from the work area. Ambient
air monitoring should be provided and ventilation should be located at
floor level. Protect cylinders against physical damage, and secure to
prevent falling or rolling. Because phosgene reacts with water, great
care should be taken to prevent contamination with water, since this
could lead to increased pressure in the tanks with possible resultant
rupture. Phosgene containers should be frequently inspected for
damage and prolonged storage should be avoided.
4.4 Transport
Phosgene may be transported in appropriately designed cylinders
as a compressed gas. Transport must comply with guidelines from
international bodies, as well as regulations at the national and local
levels regarding the movement of hazardous materials. It should be in
rigid corrosion-resistant steel containers regularly inspected for
damage and conforming to design specifications specific for phosgene.
All containers must be well-labelled and protected from damage in
shipment. Acceptable modes of transportation are road and water.
4.5 Spillage and disposal
4.5.1 Spillage
Skin contact with liquid and inhalation of gaseous phosgene
should be avoided. Non-essential people should be kept away and the
area isolated. People in the immediate vicinity should be moved to an
area upwind until the gas has dispersed. Those involved in clean-up
operations of large spills without fire should be provided with fully
encapsulated protective clothing, and self-contained breathing
apparatus. Fire-fighter's normal protective clothing will provide
limited protection for short-term exposures only. For large spills a
dyke should be made well ahead of liquid spill for later disposal.
Water should not be allowed to enter the area inside the dyke or to
enter any containers.
Liquid spills can be covered with sodium hydrogen carbonate or an
equal mixture of soda ash and slake lime or crystallized urea. Water
from an atomizer can then be added cautiously and the mixture
transferred to a large volume of water. Gas spills can be mitigated
by gaseous ammonia, aqueous ammonia or an ammonia steam curtain or
sprays.
There should be a holding area beneath any storage or handling
installation that can contain a liquid spill. This should have an
impermeable flexible membrane liner and must already contain lime,
limestone, sodium hydrogen carbonate, urea or any other suitable
neutralizing absorbent, sufficient to eliminate the spill.
4.5.2 Disposal
Dilute aqueous phosgene wastes can best be handled through
caustic scrubbing in packed columns or by scrubbing in towers with
activated carbon and water. Phosgene or aqueous phosgene wastes
should never be disposed of into sewers without prior alkaline
neutralization.
Phosgene should not be introduced into an incinerator. However,
if a product containing, or capable of producing phosgene is entering
an incinerator, then there must be an adequate scrubbing installation
to remove phosgene and/or HCl from the issuing gases. These
techniques must conform to all local and national regulations.
Welding and disposal of tanks and equipment used to handle
phosgene should take place only after all residual phosgene has been
purged from these materials.
4.6 Other protective measures
Paint removers and non-flammable dry cleaning solvents (e.g.,
carbon tetrachloride, chloroform, tri- and tetrachloroethylene and
methylene chloride) should never be used in closed areas in the
presence of fire or heaters of any kind since they can decompose to
phosgene. Welding or heat-treating vessels or equipment that may have
contained such materials should be avoided until they have been purged
of all residual chemical.
Contaminated protective clothing should not be taken home. It
must be decontaminated on site with care to avoid direct contact with
cleaning staff or other employees. It should be segregated in the
workplace in such a manner so as to avoid direct contact with cleaning
staff or other employees.
5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION
Phosgene hydrolyses in the presence of water or after adsorption
onto soil and vegetation to form hydrochloric acid and carbon dioxide.
However, plants can be killed by phosgene or hydrochloric acid after
exposure to spills or high levels of industrial emissions. Aquatic
organisms are at little risk from phosgene levels normally found in
industrial effluents. However, concentrations of hydrochloric acid
arising from spills will be high enough to alter significantly the pH
of the water and to alter aquatic life cycles. The physico-chemical
properties of phosgene preclude its bioaccumulation or
biomagnification.
6. SUMMARY OF CHEMICAL SAFETY INFORMATION
The material in this section is based on the IPCS International
Chemical Safety Card number 7. This card should be easily available
to all health workers concerned with, and users of, phosgene. It
should be displayed at, or near, entrances to areas where there is
potential exposure to phosgene and on processing equipment and
containers. The card should be translated into the appropriate
language(s). All persons potentially exposed to the chemical should
also have the instructions on the chemical safety card clearly
explained.
SUMMARY OF CHEMICAL SAFETY INFORMATION
PHOSGENE
COC12
PHYSICAL PROPERTIES OTHER CHARACTERISTICS
Relative molecular mass 98.9 Colourless gas, or colourless compressed
Melting point (°C) -127.8 liquefied gas with characteristic odour.
Boiling point (°C) 7.5 However, the odour warning when the
Relative density of the liquid (water=1) 1.4 exposure limit value is exceeded is
Solubility in water Reaction insufficient. The vapour is heavier than air
Vapour pressure, kPa at 20 °C 161.6 and may travel along the ground.
Relative vapour density (air=1) 3.42 Decomposes above 300 °C to corrosive and
toxic gases (chlorine, hydrogen chloride, and
carbon monoxide). Reacts rapidly with
ammonia, amines, aluminium and many
other chemicals; in some cases, forming
shock-sensitive products
ACUTE HAZARDS/SYMPTOMS PREVENTION AND PROTECTION FIRST AID/FIRE-FIGHTING
SKIN: Corrosive redness, skin burns, Cold-insulating gloves, protective clothing ON FROSTBITE: rinse with plenty of
pain, in cases of frostbite from liquid; water, do NOT remove clothes, rinse skin
blisters with plenty of water or shower, and
immediately refer for medical attention
EYES: Redness, pain, blurred vision Face shield or eye protection in First rinse with plenty of water for several
combination with breathing protection minutes (remove contact lenses if easily
possible), then take to a doctor
SUMMARY OF CHEMICAL SAFETY INFORMATION (con't)
ACUTE HAZARDS/SYMPTOMS PREVENTION AND PROTECTION FIRST AID/FIRE-FIGHTING
INHALATION: Pungent cough, laboured Ventilation, local exhaust, or breathing Fresh air, complete rest, half-upright
breathing, shortness or breath, sore throat protection. Wear indicator badges position, artificial respiration if indicated
and refer for medical attention as soon as
possible. The symptoms of lung oedema often
do not become manifest for up to 24 h and
they are aggravated by physical effort. Rest
and medical observation are therefore
essential. Immediate administration of an
appropriate spray, by a doctor or a person
authorized by him/her, should be considered
SPILLAGE STORAGE FIRE AND EXPLOSION
Evacuate danger area, create an aqueous Fire-proof if in building, isolated from No open flames or other sources of high
ammonia spray curtain to neutralize gas work area and other chemicals on a temperatures. Phosgene is non-flammable
cloud, consult an expert, ventilation; perforated floor over disposal tank and non-oxidative but cylinders may rupture
cautiously neutralize spilled liquid with containing soda ash/ slaked lime in cool if heated. Therefore, in case of fire in
sodium hydrogen carbonate or an equal dry location with ventilation along the surroundings remove all phosgene-containing
mixture of soda ash and slaked lime or floor. Ambient air monitoring should vessels. If not possible, keep cylinders
crystallized urea (extra personal be provided cool by spraying with water. On flames use
protection: complete protective clothing foam, powder or carbon dioxide
including self-contained breathing
apparatus)
7. CURRENT REGULATIONS, GUIDELINES AND STANDARDS
The information in this section has been extracted from the
International Register of Potentially Toxic Chemicals (IRPTC) legal
file and other UN sources. It is a representative but non-exhaustive
overview of current regulations, guidelines and standards.
Regulations and guidelines about chemicals can be fully understood
only within the framework of a country's legislation, and are always
subject to change. Therefore, they should always be verified with the
appropriate authorities.
7.1 Occupational exposure limit values
Some examples of exposure limit values in several countries are
given in the table.
7.2 Labelling, packing and transport
Internationally, transportation of phosgene is limited on
passenger-carrying ships and is forbidden on passenger and cargo
aircraft. Some countries extend this to passenger railcars.
Phosgene is classed as an IMO Class 2 hazard requiring labelling
with UN number 1076 and labels showing it to be a poisonous gas and
corrosive.
CURRENT REGULATIONS, GUIDELINES AND STANDARDS
Occupational Exposure Limit Valuesa
Country/organization Exposure limit descriptionb Value Effective datec
(mg/m3)
Australia Time-weighted average (TWA) 0.4 1990
Belgium Time-weighted average (TWA) 0.4 1991R
Czech Republic Time-weighted average (TWA) 0.5 1985
Denmark Short-term exposure limit (STEL) 0.2 1991R
Finland Short-term exposure limit (STEL) 0.2 1991R
France Short-term exposure limit (STEL) 0.4 1991R
Germany Time-weighted average (TWA) 0.4 1994
Japan Time-weighted average (TWA) 0.4 1991R
Poland Time-weighted average (TWA) 0.5 1991R
United Kingdom Time-weighted average (TWA) 0.4 1991R
USA: ACGIH Time-weighted average (TWA) 0.4 1995
USA: NIOSH/OSHA Time-weighted average (TWA) 0.4 1990
USSR Time-weighted average (TWA) 0.4 1991R
Short-term exposure limit (STEL) 0.5 1991R
a From: ILO (1991) and national lists.
b TWA = time-weighted average (8 h or 10 h shift); STEL = short-term (15 min TWA) exposure
limit not to be exceeded at any time during a shift.
c Where effective date is not reported, the date given is for the reference publication and
marked 1991R.
BIBLIOGRAPHY
Borak J (1991) Phosgene toxicity: review and update. CEM Report,
5: 19-21.
Clayton GD & Clayton FE (1994) Patty's industrial hygiene and
toxicology, 4th ed. New York, Chichester, John Wiley and Sons.
Diller WF (1985a) Therapeutic strategy in phosgene poisoning. Toxicol.
Ind Health, 1: 93-99.
Diller WF (1985b) Late sequelae after phosgene poisoning: a literature
review. Toxicol Ind Health, 1: 129-136.
HSE (1995) Phosgene. In: Critical document summaries: Synopses of the
data used in setting occupational exposure limits. London, Health and
Safety Executive, pp 24-25 (EH 64 1995 Supplement).
HSDB (1996) Hazardous substances data bank. Bethesda, Maryland,
National Library of Medicine (CD-ROM version - Micromedex, Inc.,
Denver).
ILO (1983) In: Parmeggiani L ed., Encyclopedia of occupational health
and safety, 3rd revis. ed., Geneva, International Labour Office,
Vol. 2.
IPCS (1997) Environmental Health Criteria 193: Phosgene. Geneva, World
Health Organization, International Programme on Chemical Safety.
NIOSH (1990) Pocket guide to chemical hazards. Cincinnati, Ohio,
National Institute for Occupational Safety and Health, (DHHS (NIOSH)
Publication No. 90-117).
SCHNEIDER W & DILLER W (1989) Phosgene. In: Encyclopedia of industrial
chemicals, 5th ed. Weinheim, Germany, VCH Verlag, vol. A19,
pp 411-420.