Medical Management Guidelines for Methyl Isocyanate
(C2H3NO)
CAS# 624-83-9
UN# 2480
PDF Versionpdf icon[182 KB]
Synonyms include isocyanomethane, isocyanatomethane,
methylcarbylamine, and MIC.
- Persons exposed only to methyl isocyanate gas pose no
risk of secondary contamination. Persons whose skin or clothing
is contaminated with liquid methyl isocyanate can secondarily
contaminate rescuers by direct contact or through offgassing
of vapor.
- At temperatures below 39ºC (102ºF), methyl isocyanate
is a very flammable colorless liquid that readily evaporates
when exposed to air. Gaseous methyl isocyanate is slightly
heavier than air.
- Although methyl isocyanate has a pungent odor, adverse
health effects have been reported at or below the human
odor threshold; therefore, odor detection is not a reliable
indicator of exposure.
- Methyl isocyanate is readily absorbed through the upper
respiratory tract. Methyl isocyanate can also be absorbed
through the digestive tract or skin.
General Information
Description
At temperatures below 39ºC (102ºF),
methyl isocyanate is a very flammable liquid that readily
evaporates when exposed to air. Gaseous methyl isocyanate
is approximately 1.4 times heavier than air. Methyl isocyanate
liquid is colorless with a pungent odor. Most people can smell
methyl isocyanate vapors at levels as low as 2 to 5 ppm. Methyl
isocyanate is handled and transported as a very flammable
and explosive liquid.
Routes of Exposure
Inhalation
Inhalation is the major route of exposure
to methyl isocyanate. The vapors are readily absorbed through
the lungs. The odor threshold is approximately 100 to 250
times higher than the OSHA PEL-TWA (0.02 ppm). Significant
exposures to methyl isocyanate occur primarily in occupational
settings. Acute exposure to methyl isocyanate vapors below
the odor threshold can be irritating to the eye and respiratory
epithelium. Acute exposure to higher vapor concentrations
may cause severe pulmonary edema and injury to the alveolar
walls of the lung and death. Survivors of acute exposures
may exhibit long-term respiratory effects. Odors of methyl
isocyanate may not provide adequate warning of hazardous concentrations
because the Immediately Dangerous to Life or Health (IDLH)
limit is only 3 ppm and the threshold for detection of methyl
isocyanate vapors ranges from 2 to 5 ppm in humans. Significant
exposure to methyl isocyanate vapors would most likely be
the result of accidental release of methyl isocyanate to the
air such as occurred in Bhopal, India in 1984, where the primary
effect was pulmonary edema with some alveolar wall destruction.
Methyl isocyanate is heavier than air; therefore, exposure
in poorly ventilated, enclosed, or low-lying areas could result
in asphyxiation.
Children exposed to the same levels of
methyl isocyanate as adults may receive larger doses because
they have relatively greater lung surface area:body weight
ratios and higher minute volume:weight ratios. In addition,
they may be exposed to higher levels than adults in the same
location because of their short stature and the higher levels
of methyl isocyanate found nearer to the ground. Children
may be more vulnerable to corrosive agents than adults because
of the smaller diameter of their airways.
Skin/Eye Contact
Direct contact with liquid or concentrated
vapors of methyl isocyanate may cause irritation of the skin
or eyes and severe ocular damage. Direct skin contact may
result in dermal absorption. Significant dermal exposure to
methyl isocyanate would not likely occur outside an occupational
environment in which methyl isocyanate is stored or used.
Because of their relatively larger surface
area:weight ratio, children are more vulnerable to toxicants
absorbed through the skin.
Ingestion
Although unlikely, ingestion of liquid
methyl isocyanate could produce severe gastrointestinal irritation.
Sources/Uses
Methyl isocyanate is made by reacting
methylamine with phosgene. The primary use of methyl isocyanate
is as a chemical intermediate in the production of pesticides.
It is also used to produce polyurethane foams and plastics.
Standards and Guidelines
OSHA PEL (permissible exposure limit)
= 0.02 ppm (averaged over an 8-hour workshift) with a skin
notation
NIOSH IDLH (immediately dangerous to
life or health) = 3 ppm
AIHA ERPG-2 (maximum airborne concentration
below which it is believed that nearly all persons could be
exposed for up to 1 hour without experiencing or developing
irreversible or other serious health effects or symptoms that
could impair their abilities to take protective action) =
0.5 ppm
Physical Properties
Description: Colorless liquid
at room temperature; volatile, flammable, explosive in air
Warning properties: Pungent odor
of methyl isocyanate may not be adequate to warn of acute
exposure. Most people can detect methyl isocyanate at levels
of 2 to 5 ppm (1 ppm is equivalent to 2.35 mg/m³)
Molecular weight: 57.05 daltons
Boiling point (760 mm Hg): 102ºF
(39.1ºC)
Freezing point: -49ºF (-45ºC)
Vapor pressure: 348 mm Hg at 68ºF
(20ºC)
Vapor density: 1.42 (air = 1.00)
Water solubility: 6.7% at 68ºF
(20ºC)
Flammability: highly flammable
Flammable Range: 5.3% to 26% (concentration
in air)
Incompatibilities
Methyl isocyanate reacts violently with
water. Methyl isocyanate is incompatible with oxidizers, acids,
alkalis, amines, iron, tin, and copper.
Health Effects
- Methyl isocyanate is irritating and corrosive to the eyes,
respiratory tract, and skin. Acute exposure to high vapor
concentrations may cause severe pulmonary edema and injury
to the alveolar walls of the lung, severe corneal damage,
and death. Survivors of acute exposures may exhibit long-term
respiratory and ocular effects. Methyl isocyanate may be
a dermal and respiratory sensitizer.
- Mechanisms of methyl isocyanate-induced toxicity are not
known. Persistent respiratory and ocular effects may reflect
methyl isocyanate-induced immunologic effects. Methyl isocyanate
may cross the placenta and enter a developing fetus. Individuals
especially susceptible to the toxic effects of methyl isocyanate
include those with existing disorders of the respiratory
system or eyes.
Acute Exposure
Mechanisms of toxicity have not been
clearly elucidated for methyl isocyanate; however, carbamylation
of globin and blood proteins may play a role. Persistent respiratory
and ocular effects may reflect methyl isocyanate-induced immunologic
effects since antibodies specific to methyl isocyanate have
been demonstrated in the blood of exposed patients. Methyl
isocyanate is highly reactive; therefore, it is not metabolized
in the classical sense. The onset of respiratory effects following
acute exposure to methyl isocyanate can be immediate in some
cases. In others, respiratory injury can evolve over periods
of hours or days. Exposure-related deaths sometimes can occur
as late as 30 or more days post-exposure, due in part to the
development of pneumonia.
Children do not always respond to chemicals
in the same way that adults do. Different protocols for managing
their care may be needed.
Respiratory
Methyl isocyanate vapors are severely
irritating and corrosive to the respiratory tract. Symptoms
may include cough, chest pain, dyspnea, coma, and death. Irritative
respiratory symptoms such as pulmonary edema and bronchial
spasms may occur in immediate response to exposure. Methyl
isocyanate-induced pulmonary edema may progress to effects
such as alveolar wall destruction and pneumonia, which may
ultimately lead to respiratory failure and death. Some respiratory
effects may progress in severity over a period of hours to
days post-exposure. Asthmatic reactions and long-term respiratory
effects have been reported.
Children may be more vulnerable to corrosive
agents than adults because of the smaller diameter of their
airways. Children also may be more vulnerable to gas exposure
because of relatively higher minute ventilation per kg and
failure to evacuate an area promptly when exposed.
Ocular/Ophthalmic
Severe eye irritation can result from
exposure to methyl isocyanate vapors or direct contact with
the liquid. Symptoms may include immediate eye pain, lacrimation,
photophobia, profuse lid edema, and corneal ulcerations. Ocular
exposure may result in long-term or permanent eye damage.
Dermal
Methyl isocyanate is a skin irritant
and may cause chemical burns upon dermal contact at high exposure
levels.
Because of their relatively larger surface
area: body weight ratio, children are more vulnerable to toxicants
that affect the skin.
Gastrointestinal
Nausea, vomiting, abdominal pain, and
defecation have been reported after acute exposure to methyl
isocyanate vapors.
Potential Sequelae
Initial irritative symptoms of the respiratory
tract may progress to more serious respiratory injury over
a period of hours to days following exposure to methyl isocyanate
vapors. Compromised lung tissue may be susceptible to bacterial
pneumonias. Exposure may result in permanent eye damage. Methyl
isocyanate may also be a respiratory and dermal sensitizer.
Renal tubular necrosis, reduced liver function, and miscarriage
were associated with methyl isocyanate exposure in the Bhopal,
India incident.
Chronic Exposure
Chronic exposure to methyl isocyanate
may result in chronic obstructive lung disease.
Carcinogenicity and Reproductive and Developmental Effects
Methyl isocyanate has not been classified
for carcinogenicity.
Methyl isocyanate is not included in
the list of Reproductive and Developmental Toxicants,
a 1991 report published by the U.S. General Accounting Office
that lists 30 chemicals of concern because of widely acknowledged
reproductive and developmental consequences. Increased rates
of spontaneous abortions and neonatal deaths among victims
of the Bhopal accident were observed for months following
exposure. However, the precise role of methyl isocyanate in
developmental toxicity is difficult to determine. Poor oxygenation
resulting from compromised lung function may be involved.
Animal studies indicate that inhalation exposure during gestation
may result in decreased numbers of live births and decreased
survival during lactation. There was no evidence of a dominant
lethal effect in exposed male mice. Genotoxicity testing in
animals indicates that methyl isocyanate may have the capacity
to affect chromosome structure, but it apparently does not
induce gene mutations.
Prehospital Management
- Persons exposed only to methyl isocyanate gas pose no
risk of secondary contamination to rescuers. Persons whose
skin or clothing is contaminated with liquid methyl isocyanate
can secondarily contaminate response personnel by direct
contact or through off-gassing of vapor.
- Methyl isocyanate is irritating to the eyes, respiratory
tract, and skin. Early symptoms may include eye irritation,
coughing, and shortness of breath. In cases of severe exposure,
later symptoms may include vomiting and diarrhea. Acute
exposure to high vapor concentrations may cause relatively
rapid and severe pulmonary edema, alveolar wall injury,
and corneal damage. Initial signs of irritation may progress
to vomiting, diarrhea, and death. Survivors of acute exposures
may exhibit long-term respiratory and ocular effects. Methyl
isocyanate may be a dermal and respiratory sensitizer.
- There is no antidote for methyl isocyanate. Treatment
consists of removal of the victim from the contaminated
area and support of respiratory and cardiovascular functions.
Hot Zone
Rescuers should be trained and appropriately
attired before entering the Hot Zone. If the proper equipment
is not available, or if the rescuers have not been trained
in its use, call for assistance from a local or regional hazardous
materials (HAZMAT) team or other properly equipped response
organization.
Rescuer Protection
Inhaled methyl isocyanate is a severe
respiratory tract irritant. Contamination of the skin can
cause irritation or chemical burns. Contamination of the eyes
can cause irritation and serious or long-term damage. Methyl
isocyanate is absorbed through the skin.
Respiratory protection: Positive-pressure,
self-contained breathing apparatus (SCBA) with a full facepiece
and operated in a positive pressure mode is recommended in
response to situations that involve exposure to potentially
unsafe levels of methyl isocyanate gas.
Skin protection: Chemical protective
clothing is recommended because methyl isocyanate can cause
skin irritation and burns. Protective eye equipment is recommended
to prevent eye contact.
ABC Reminders
Quickly establish a patent airway, ensure
adequate respiration and pulse. Maintain adequate circulation.
Provide supplemental oxygen if cardiopulmonary compromise
is suspected. If trauma is suspected, maintain cervical immobilization
manually and apply a cervical collar and a backboard when
feasible. Apply direct pressure to stop any heavy bleeding.
Victim Removal
If victims can walk, lead them out of
the Hot Zone to the Decontamination Zone. Victims who are
unable to walk should be removed on backboards or gurneys.
If these are not available, carefully carry or drag victims
to safety.
Consider appropriate management of anxiety
in victims with chemically-induced acute disorders, especially
children who may suffer separation anxiety if separated from
a parent or other adult.
Decontamination Zone
Patients exposed only to methyl isocyanate
gas who have no eye or skin irritation do not need decontamination.
They may be transferred immediately to the Support Zone. Other
patients will require decontamination as described below.
Rescuer Protection
If exposure levels are determined to
be safe, decontamination may be conducted by personnel wearing
a lower level of protection than that required in the Hot
Zone (described above).
ABC Reminders
Quickly establish a patent airway, ensure
adequate respiration and pulse. Maintain adequate circulation.
Provide supplemental oxygen if cardiopulmonary compromise
is suspected. If trauma is suspected, maintain cervical immobilization
manually and apply a cervical collar and a backboard when
feasible. Administer supplemental oxygen as required. Assist
ventilation with a bag-valve-mask device if necessary. Apply
direct pressure to control any heavy bleeding.
Basic Decontamination
Rapid skin decontamination is critical.
Victims who are able may assist with their own decontamination.
Remove contaminated clothing and personal belongings and place
them in double plastic bags.
Wash exposed skin thoroughly with soap
and water. Use caution to avoid hypothermia when decontaminating
victims, particularly children or the elderly. Use blankets
or warmers after decontamination as needed.
Irrigate exposed eyes with copious amounts
of tepid water for at least 15 minutes. Remove contact
lenses if they are easily removable without additional trauma
to the eye. If pain or injury is evident, continue irrigation
while transferring the victim to the Support Zone.
In cases of ingestion, do not induce
emesis. If the victim is not symptomatic, consider administering
activated charcoal at a dose of 1 g/kg (infant, child, and
adult dose). A soda can and straw may be of assistance when
offering charcoal to a child. However, the effectiveness of
activated charcoal in binding methyl isocyanate has not been
demonstrated.
If the victim is conscious and able to
swallow, consider giving 4 to 8 ounces of water.
Consider appropriate management of chemically
contaminated children at the exposure site. Also, provide
reassurance to the child during decontamination, especially
if separation from a parent occurs.
Transfer to Support Zone
As soon as basic decontamination is complete,
move the victim to the Support Zone.
Support Zone
Be certain that victims have been decontaminated
properly (see Decontamination Zone, above). Victims
who have undergone decontamination or have been exposed only
to methyl isocyanate gas pose no serious risk of secondary
contamination to rescuers. In such cases, Support Zone personnel
require no specialized protective gear.
ABC Reminders
Quickly establish a patent airway. If
trauma is suspected, maintain cervical immobilization manually
and apply a cervical collar and a backboard when feasible.
Ensure adequate respiration and pulse. Administer supplemental
oxygen as required and establish intravenous access if necessary.
Place on a cardiac monitor, if available.
Additional Decontamination
Continue irrigating exposed skin and
eyes, as appropriate.
In cases of ingestion, do not induce
emesis. If the victim is not symptomatic, consider administering
charcoal at a dose of 1 g/kg (infant, child, and adult dose).
A soda can and straw may be of assistance when offering charcoal
to a child. However, the effectiveness of activated charcoal
in binding methyl isocyanate has not been demonstrated.
If the victim is conscious and able to
swallow, consider giving 4 to 8 ounces of water if it has
not been given previously.
Advanced Treatment
Treat cases of respiratory compromise
with respiratory support using protocols and techniques available
and within the scope of training. Some cases may necessitate
procedures such as endotracheal intubation or cricothyrotomy
by properly trained and equipped personnel.
Treat patients who have bronchospasm
with oxygen, aerosolized bronchodilators such as albuterol,
and/or steroids according to established protocol.
In cases of non-cardiogenic pulmonary
edema, which may be delayed in onset, maintain adequate ventilation
and oxygenation. Early use of mechanical ventilation and positive-end-expiratory
pressure (PEEP) may be required. To minimize barotrauma and
other complications, use the lowest amount of PEEP possible
while maintaining adequate oxygenation. Consider drug therapy
for pulmonary edema.
Patients who are comatose, hypotensive,
or having seizures or cardiac arrhythmias should be treated
according to advanced life support (ALS) protocols.
If evidence of shock or hypotension is
observed begin fluid administration. For adults with systolic
pressure less than 80 mm Hg, bolus perfusion of 1,000 mL/hour
intravenous saline or lactated Ringer's solution may be appropriate.
Higher adult systolic pressures may necessitate lower perfusion
rates. For children with compromised perfusion administer
a 20 mL/kg bolus of normal saline over 10 to 20 minutes, then
infuse at 2 to 3 mL/kg/hour. Consider vasopressors if patient
is hypotensive with a normal fluid volume.
Transport to Medical Facility
Only decontaminated patients or patients
not requiring decontamination should be transported to a medical
facility. "Body bags" are not recommended.
Report the condition of the patient,
treatment given, and estimated time of arrival at the medical
facility to the base station and the receiving medical facility.
If methyl isocyanate has been ingested,
prepare the ambulance in case the victim vomits toxic material.
Have ready several towels and open plastic bags to quickly
clean up and isolate vomitus.
Multi-Casualty Triage
Consult with the base station physician
or the regional poison control center for advice regarding
triage of multiple victims. Patients who have histories or
evidence suggesting significant exposure (e.g., altered behavior,
respiratory distress, or chemical burns) should be transported
to a medical facility for evaluation.
Patients who have a history of chronic
pulmonary disease should be clinically evaluated for airflow
obstruction. Patients who have mild symptoms of respiratory
or eye irritation should be clinically evaluated because onset
of pulmonary edema may be delayed for up to 72 hours post-exposure
and eye injury may need to be treated topically for inflammation
or secondary infection.
Patients who have symptoms of transient
skin, nose, or eye irritation may be discharged from the scene
after their names, addresses, and telephone numbers are recorded.
They should be advised to rest and to seek medical care promptly
if symptoms develop or recur (see Patient Information Sheet
below).
Emergency Department Management
- Persons exposed only to methyl isocyanate gas pose no
risk of secondary contamination to rescuers. Persons whose
skin or clothing is contaminated with liquid methyl isocyanate
can secondarily contaminate response personnel by direct
contact or through off-gassing of vapor.
- Methyl isocyanate is irritating to the eyes, respiratory
tract, and skin. Acute exposure to high vapor concentrations
may cause severe pulmonary edema and injury to the alveolar
walls of the lung, severe corneal damage, and death. Survivors
of acute exposures may exhibit long-term respiratory and
ocular effects. Methyl isocyanate may be a dermal and respiratory
sensitizer.
- There is no antidote for methyl isocyanate. Treatment
consists of removal of the victim from the contaminated
area and support of respiratory and cardiovascular functions.
Decontamination Area
Previously decontaminated patients and
those exposed only to methyl isocyanate gas who have no skin
or eye irritation may be transferred immediately to the Critical
Care Area. Others require decontamination as described below.
Be aware that use of protective equipment
by the provider may cause anxiety, particularly in children,
resulting in decreased compliance with further management
efforts.
Because of their relatively larger surface
area:body weight ratio, children are more vulnerable to toxins
absorbed through the skin. Also emergency room personnel should
examine children's mouths because of the frequency of hand-to-mouth
activity among children.
ABC Reminders
Evaluate and support the airways, breathing,
and circulation. Provide supplemental oxygen if cardiopulmonary
compromise is suspected. Treat cases of respiratory compromise
with respiratory support using protocols and techniques available
and within the scope of training. Some cases may necessitate
procedures such as endotracheal intubation or cricothyrotomy
by properly trained and equipped personnel.
Treat patients who have bronchospasm
with oxygen, aerosolized bronchodilators such as albuterol,
and/or steroids according to established protocol.
Children may be more vulnerable to corrosive
agents than adults because of the smaller diameter of their
airways.
Consider racemic epinephrine aerosol
for children who develop stridor. Dose 0.25-0.75 mL of 2.25%
racemic epinephrine solution, repeat every 20 minutes as needed,
cautioning for myocardial variability.
In cases of non-cardiogenic pulmonary
edema, which may be delayed in onset, maintain adequate ventilation
and oxygenation. Mechanical ventilation and positive-end-expiratory
pressure (PEEP) may be required. To minimize barotrauma and
other complications, use the lowest amount of PEEP possible
while maintaining adequate oxygenation. Consider drug therapy
for pulmonary edema. Keep in mind that the use of steroids
to prevent or treat chemical pneumonitis and pulmonary edema
is controversial.
Patients who are comatose, hypotensive,
or are having seizures or cardiac arrhythmias should be treated
in the conventional manner.
Basic Decontamination
Patients who are able may assist with
their own decontamination.
Because methyl isocyanate can cause burns,
ED staff should don chemical-resistant jumpsuits (e.g., of
Tyvek or Saranex) or butyl rubber aprons, rubber gloves, and
eye protection if the patient's clothing or skin is wet. After
the patient has been decontaminated, no special protective
clothing or equipment is required for ED personnel.
Quickly remove contaminated clothing
while gently washing the skin with soap and water. Double-bag
the contaminated clothing and personal belongings. Handle
burned skin with caution.
Wash exposed skin thoroughly with soap
and water. If pain or injury is evident, continue irrigation
while transferring the victim to the Critical Care Area. Use
caution to avoid hypothermia when decontaminating children
or the elderly. Use blankets or warmers when appropriate.
Flush exposed or irritated eyes with
copious amounts of tepid water for at least 15 minutes.
Remove contact lenses if easily removable without additional
trauma to the eye. If pain or injury is evident, continue
irrigation while transferring the victim to the Critical Care
Area.
In cases of ingestion, do not induce
emesis. If the victim is not symptomatic, consider administering
activated charcoal at a dose of 1 g/kg (infant, child, and
adult dose). A soda can and straw may be of assistance when
offering charcoal to a child. However, the effectiveness of
activated charcoal in binding methyl isocyanate has not been
demonstrated.
If the victim is conscious and able to
swallow, consider giving 4 to 8 ounces of water.
Critical Care Area
Be certain that appropriate decontamination
has been carried out.
ABC Reminders
Evaluate and support the airways, breathing,
and circulation as in ABC Reminders above. Establish
intravenous access in seriously ill patients. Continuously
monitor cardiac rhythm.
Patients who are comatose, hypotensive,
or are having seizures or cardiac arrhythmias should be treated
in the conventional manner.
Inhalation Exposure
Administer supplemental oxygen by mask
to patients who have respiratory complaints. Treat patients
who have bronchospasm with aerosolized bronchodilators such
as albuterol and/or steroids.
In cases of non-cardiogenic pulmonary
edema, which may be delayed in onset, maintain adequate ventilation
and oxygenation. Monitor arterial blood gases and/or pulse
oximetry. If a high FIO2 is required to maintain
adequate oxygenation, mechanical ventilation and positive-end-expiratory
pressure (PEEP) may be required. To minimize barotrauma and
other complications, use the lowest amount of PEEP possible
while maintaining adequate oxygenation. Consider drug therapy
for pulmonary edema. Keep in mind that the use of steroids
to prevent or treat chemical pneumonitis and pulmonary edema
is controversial. Antibiotics should be used as indicated
to control infection. Damaged lower respiratory tissue might
be more susceptible to infection.
Skin Exposure
If concentrated methyl isocyanate is
in contact with the skin, chemical burns may result; treat
as thermal burns.
Because of their relatively larger surface
area:body weight ratio, children are more vulnerable to toxicants
that affect the skin.
Eye Exposure
Continue irrigation for at least 15 minutes.
Test visual acuity. Examine the eyes for corneal damage and
treat appropriately. Immediately consult an ophthalmologist
for patients who have suspected severe corneal injuries.
Ingestion
Do not induce emesis. Consider
endoscopy to evaluate the extent of gastrointestinal-tract
injury. Extreme throat swelling may require endotracheal intubation
or cricothyrotomy. Gastric lavage is useful in certain circumstances
to remove caustic material and prepare for endoscopic examination.
Consider gastric lavage with a small nasogastric (NG) tube
if: (1) a large dose has been ingested; (2) the patient's
condition is evaluated within 30 minutes; (3) the patient
has oral lesions or persistent esophageal discomfort; and
(4) the lavage can be administered within 1 hour of ingestion.
Care must be taken when placing the gastric tube because blind
gastric-tube placement may further injure the chemically damaged
esophagus or stomach.
Because children do not ingest large
amounts of corrosive materials, and because of the risk of
perforation from NG intubation, lavage is discouraged in children
unless intubation is performed under endoscopic guidance.
If the victim is not symptomatic, consider
administering activated charcoal at a dose of 1 g/kg (infant,
child, and adult dose). A soda can and straw may be of assistance
when offering charcoal to a child. However, the effectiveness
of activated charcoal in binding methyl isocyanate has not
been demonstrated.
Consider giving 4 to 8 ounces of water
to alert patients who can swallow, if not done previously.
Antidotes and Other Treatments
There is no antidote for methyl isocyanate.
Treatment is supportive of respiratory and cardiac functions.
Laboratory Tests
Routine laboratory studies include chest
radiography and pulse oximetry (or ABG measurements).
Disposition and Follow-up
Consider hospitalizing symptomatic patients
who have evidence of respiratory or cardiac distress or significant
chemical burns.
Delayed Effects
Acute exposure to high concentrations
of methyl isocyanate may result in delayed onset of pulmonary
edema and risk of secondary infection of the lungs or eyes.
Patient Release
Patients who become totally asymptomatic
in terms of pulmonary complaints in a 72-hour observation
period are not likely to develop complications. They may be
released and advised to rest and to seek medical care promptly
if symptoms develop (see the Methyl Isocyanate--Patient
Information Sheet below). Cigarette smoking can exacerbate
pulmonary injury and should be discouraged for 72 hours after
exposure.
Follow-up
Obtain the name of the patient's primary
care physician so that the hospital can send a copy of the
ED visit to the patient's doctor.
Follow-up evaluation of respiratory function
should be arranged for severely exposed patients. Patients
who have skin or corneal lesions should be reexamined within
24 hours.
Reporting
If a work-related incident has occurred,
you might be legally required to file a report; contact your
state or local health department.
Other persons might still be at risk
in the setting where this incident occurred. If the incident
occurred in the workplace, discussing it with company personnel
might prevent future incidents. If a public health risk exists,
notify your state or local health department or other responsible
public agency. When appropriate, inform patients that they
may request an evaluation of their workplace from the Occupational
Safety and Health Administration (OSHA) or the National Institute
for Occupational Safety and Health (NIOSH). See Appendix III
for a list of agencies that may be of assistance.
Patient Information Sheet
This handout provides information and
follow-up instructions for persons who have been exposed to
methyl isocyanate.
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What is methyl isocyanate?
Methyl isocyanate is a very flammable
liquid that readily evaporates when exposed to air. Methyl
isocyanate liquid is colorless with a pungent odor. The primary
use of methyl isocyanate is as a chemical intermediate in
the production of pesticides. It is also used to produce polyurethane
foams and plastics. It is shipped and handled as a flammable
and explosive liquid in a special container.
What immediate health effects can be caused by exposure to methyl isocyanate?
Methyl isocyanate vapors are severely
irritating and corrosive to the respiratory tract and eyes.
Symptoms may include cough, chest pain, shortness of breath,
watery eyes, eye pain (particularly when exposed to light),
profuse lid edema, and corneal ulcerations. Respiratory symptoms
such as pulmonary edema and bronchial spasms may occur in
immediate response to exposure or develop and progress in
severity over a period of hours to days post-exposure. Acute
exposure to very high concentrations may be quickly fatal
due to respiratory failure. Methyl isocyanate is a skin irritant
and may cause chemical burns upon dermal contact.
Can methyl isocyanate poisoning be treated?
There is no antidote for methyl isocyanate,
but its effects can be treated. Persons who have inhaled large
amounts of methyl isocyanate would most likely need to be
hospitalized. Persons who have come into direct skin or eye
contact with methyl isocyanate liquid or vapors may need to
be treated for chemical burns or serious eye injury.
Are any future health effects likely to occur?
A single exposure from which a person
recovers quickly may not result in long-term health effects.
However, some respiratory and eye damage may persist for a
long time after exposure to methyl isocyanate. The chemical
may also be a dermal and respiratory sensitizer, causing reactive
responses upon subsequent exposures.
What tests can be done if a person has been exposed to methyl isocyanate?
Specific tests for the presence of methyl
isocyanate in blood or urine are not generally useful. If
a severe exposure has occurred, blood analyses, x-rays, and
breathing tests might show whether the lungs have been injured.
Where can more information about methyl isocyanate be found?
More information about methyl isocyanate
can be obtained from your regional poison control center;
your state, county, or local health department; the Agency
for Toxic Substances and Disease Registry (ATSDR); your doctor;
or a clinic in your area that specializes in occupational
and environmental health. If the exposure happened at work,
you might be required to contact your employer and the Occupational
Safety and Health Administration (OSHA), or the National Institute
for Occupational Safety and Health (NIOSH). Ask the person
who gave you this form for help locating these telephone numbers.
Follow-up Instructions
Keep this page and take it with you to
your next appointment. Follow only the instructions
checked below.
Print this handout only.pdf icon[PDF - 57.8 KB]
[ ] Call your doctor or the Emergency
Department if you develop any unusual signs or symptoms within
the next 24 hours, especially:
- eye, nose, throat irritation
- coughing or wheezing
- difficulty breathing or shortness of breath
- chest pain or tightness
- nausea, vomiting, diarrhea, or stomach pain
[ ] No follow-up appointment is necessary
unless you develop any of the symptoms listed above.
[ ] Call for an appointment with Dr.____
in the practice of ________.
When you call for your appointment, please
say that you were treated in the Emergency Department at _________
Hospital by________and were advised to be seen again in ____days.
[ ] Return to the Emergency Department/Clinic
on ____ (date) at _____ AM/PM for a follow-up examination.
[ ] Do not perform vigorous physical
activities for 1 to 2 days.
[ ] Do not return to work for _____days.
[ ] You may return to work on a limited
basis. See instructions below.
[ ] Avoid exposure to cigarette smoke
for 72 hours; smoke may worsen the condition of your lungs.
[ ] Avoid drinking alcoholic beverages
for at least 24 hours; alcohol may worsen injury to your stomach
or have other effects.
[ ] Avoid taking the following medications:
________________
[ ] You may continue taking the following
medication(s) that your doctor(s) prescribed for you: _______________________________
[ ] Other instructions:
____________________________________
_____________________________________________________
- Provide the Emergency Department with the name and the
number of your primary care physician so that the ED can
send him or her a record of your emergency department visit.
- You or your physician can get more information on the
chemical by contacting: ____________ or _____________, or by
checking out the following Internet Web sites:
___________;__________.
Signature of patient _______________ Date ____________
Signature of physician _____________ Date ____________
Where can I get more information?
If you have questions or concerns, please contact your community or state health or environmental quality department or:
For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
4770 Buford Highway
Chamblee, GA 30341-3717
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO
ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.