United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9360.7-13FS
September 1993
PB93-963424
xvEPA Superfund Guide
Reportable Quantity Adjustment for Methyl
Isocyanate (MIC)
Office of Emergency and Remedial Response
Emergency Response Division 5202G
Quick Reference Fact Sheet
Methyl isocyanate (MIC) is a toxic and highly volatile chemical used primarily in the production of pesticides.
Public awareness of this substance was heightened during 1984, when a gaseous cloud of MIC was released
from a chemical plant in Bhopal, India. MIC is regulated under the Clean Air Act (CAA) and as a hazardous
waste under the Resource Conservation and Recovery Act (RCRA). By virtue of these listings, it is also a
hazardous substance under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA). Under CERCLA, an adjusted reportable quantity (RQ) for MIC of 10 pounds was published in the
Federal Register on June 30, 1993 (58 FR 35314). Reporting a release of a CERCLA hazardous substance
when the RQ threshold has been reached or exceeded provides timely information that will enable Federal,
State, and local governments to quickly evaluate the need for a response, based on the potential exposure
Jiazard. This fact sheet contains a discussion of the RQ adjustment and release reporting process, the basis for
the current RQ adjustment to 10 pounds for MIC, and information about the facilities that handle MIC.
WHAT IS AN RQ?
An RQ is the quantity of a hazardous substance which,
if released into the environment within a 24-hour
period, must be reported to appropriate government
response personnel. Under CERCLA and the
Emergency Planning and Community Right-to-Know
Act of 1986 (EPCRA), certain parties are required to
report any release of a hazardous substance into the
environment as soon as the person has knowledge of
the release, and if the amount released is equal to or
greater than the RQ for that hazardous substance. RQs
serve as triggers for informing the government of
releases of CERCLA hazardous substances so that
Federal, State, and local personnel can determine
whether government participation is required for an
appropriate response. CERCLA establishes a one-
pound statutory RQ for most substances unless and
until final adjusted RQs are established by regulation.
An RQ is a relative indication of the potential hazards
associated with the release of a hazardous substance,
rather than a measure of absolute levels of risk, which
depends on the specific circumstances of the release.
Table of Contents
What is an RQ? 1
How is the RQ for a Chemical Determined? . . 2
Exhibit 1: Assignment of a Reportable
Quantity 2
What Happens When a Hazardous Substance is
Released? 2
What is MIC? 2
What Facilities Generate or Use MIC? 3
Release of MIC in Bhopal, India 3
What is the RQ for MIC and Why? 3
Other Reference Material 4
1
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The list of hazardous substances is found in section
302.4 of Title 40 of the Code of Federal Regulations.
CERCLA defines "hazardous substance" to include
certain substances regulated under the Clean Water
Act, the CAA, RCRA, and the Toxic Substances
Control Act. CERCLA also allows EPA to designate
additional hazardous substances that may present
substantial danger to public health or welfare or the
environment when released.
HOW IS THE RQ FOR A CHEMICAL
DETERMINED?
Under the methodology used to establish the RQ of a
CERCLA hazardous substance, EPA evaluates data on
six physical, chemical, and toxicological properties of
the substance (see Exhibit 1). These properties, or
"primary criteria," identify a chemical's toxicity to fish
and mammals; its ability to cause adverse effects from
chronic exposure, including cancer; and the potential
of a chemical to ignite or dangerously react with air,
water, or with itself. Based on its evaluation, EPA
assigns one of five possible RQs (1, 10, 100, 1000, or
5000 pounds) for each of the primary criteria (except
radionuclides). The lowest of these six RQs becomes
the primary criteria RQ for the hazardous substance.
After EPA assigns the primary criteria RQ, the
Agency evaluates each substance for its potential to
break down when it is released into the environment.
The primary criteria RQ can either be raised if the
hazardous substance quickly reacts to form a less
hazardous product or lowered if it reacts to form a
more hazardous product.
WHAT HAPPENS WHEN A HAZARDOUS
SUBSTANCE IS RELEASED?
Reporting Requirements
Any release into the environment of an RQ of a
hazardous substance (over a 24-hour period) must be
reported immediately to the National Response Center
at 800-424-8802 or 202-267-2675. In addition,
EPCRA requires that the release be reported to the
appropriate State emergency response commission
(SERC) and local emergency planning committee
(LEPC). The phone number for the SERC and LEPC
in each State is available through the EPCRA Hotline
at 800-525-0202 or 703-412-9877. For transportation-
related releases, dialing 911 (or the telephone operator)
will satisfy the EPCRA notification requirements.
,
Primary Criteria
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5000 5000 Utf, 100 N-A.
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Secondary Criteria
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biodegradation, hydrolysis, or photolysis?
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Exhibit 1
Assignment of a Reportable Quantity
Liability and Penalties
The person in charge of a facility or vessel and other
parties who transport or dispose of hazardous
substances are liable for all response costs and
natural resource damages resulting from a release of
a CERCLA hazardous substance. This includes the
costs of cleanup and any health study resulting from
the release. This liability applies even if a release is
not reportable because the amount of the substance
released is less than the RQ. In addition, if the
person in charge of a vessel or facility fails to report
a release that equals or exceeds its RQ or submits
false or misleading information regarding a release,
EPA is authorized to impose civil penalties and may
seek the imposition of criminal sanctions.
WHAT IS MIC?
MIC is a toxic and volatile chemical that is used as
an intermediate to form other substances in the
production of insecticides and herbicides and in the
manufacture of polyurethane and certain plastics. At
room temperature, MIC is a volatile colorless liquid.
It exists as a vapor in the atmosphere, but breaks
down quickly when mixed with water.
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Public awareness of the toxic effects of MIC were
limited until MIC was released at Bhopal, India in
1984. Prior to the Bhopal incident, the potentially
harmful characteristics of MIC in humans had not been
widely evaluated. Because MIC typically was used as
an intermediate chemical in closed production
processes, the possibility of a release into the
atmosphere and exposure to humans was thought to be
highly unlikely. The first studies addressing the
human health risks and other hazards of this chemical
were published in 1985.
WHAT FACILITIES GENERATE OR USE MIC?
There are two major chemical facilities in this country
that produce and use MIC to manufacture insecticides:
a Rhone-Poulenc facility in Institute, West Virginia
and a DuPont facility in LaPorte, Texas. Rhone-
Poulenc manufactures, stores underground, and
transports MIC by pipeline to on-site facilities which
then use it in the production process. At the DuPont
facility, MIC is produced and immediately reacted in a
closed production process and is not stored or
transported from this site. Security measures are in
place at both facilities and access to each site is
controlled to minimize the potential for releases.
RELEASE OF MIC IN BHOPAL, INDIA
During a two to three hour period on the night of
December 2, 1984, an estimated 40,000 pounds of
MIC were released into the atmosphere over Bhopal,
India. The release occurred when water was added to
an above-ground tank containing MIC. This initiated a
rapid heat-producing process resulting in a vapor cloud
of pungent odor which blanketed the city. The vapor
cloud resulted in extended exposure to the people in
Bhopal who inhaled the toxic compound. The
exposure to the chemical killed more than 2,000 people
and seriously injured more than 60,000 people.
Subsequent autopsies concluded that severe damage to
the lungs was the main cause of death. Some of the
exposed people died within minutes of exposure after
initial weakness and fainting. Survivors of the incident
experienced initial eye, nose, and throat irritation, and
coughing and choking sensations. Survivors also
experienced ulcerated corneas (which eventually
healed) and lung damage resulting in breathing
difficulties especially during strenuous activities and
sleep. Finally, of the women who were pregnant at
the time of release in Bhopal, only 66% gave birth to
live babies, of which 14% died within 30 days. This
is between five and six times the normal infant
mortality rate of the Bhopal region.
WHAT IS THE RQ FOR MIC AND WHY?
The one-pound statutory RQ for MIC was proposed
for adjustment to 100 pounds in a Federal Register
notice that was published on May 8, 1992 (57 FR
20014). The 100-pound proposed RQ was based on
MIC's chronic (long-term exposure) toxicity and the
fact that it breaks down readily in water. In response
to public comments received on the proposed rule,
EPA reevaluated the tendency of MIC to break down
when released to the environment. The evaluation
showed that MIC releases are more likely to be to air
than to water and that the rate that MIC breaks down
in air may not be sufficient to meet the criteria for
raising the RQ one level to 100 pounds. Therefore,
in the final rulemaking published on June 30, 1993
(58 FR 35314), EPA used chronic toxicity as the
basis for adjusting the statutory one-pound RQ for
MIC to 10 pounds.
EPA believes that the 10-pound RQ for MIC is an
adequate reporting level that will provide Federal,
State, and local governments with timely information
about the most serious releases of MIC, and will
avoid over-reporting of releases that normally will
not require a government response. Once a report of
an MIC release is received, regardless of its size, it
will be evaluated in light of the specific
circumstances of the release to determine whether a
government response action is required.
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For more information contact:
RCRA/Superfund Hotline
(800) 424-9346
(703) 412-9810 in the D.C. metropolitan area
TDD hotline: (800) 553-7672/(703) 486-3323
or
Ms. Gerain H. Perry
Response Standards and Criteria Branch
Emergency Response Division (5202G)
U.S. Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
OTHER REFERENCE MATERIAL
For additional information on the RQ adjustment
methodology, see the preamble to the April 4, 1985
final rule (50 FR 13456). This document discusses
the methodology and criteria used in the RQ
adjustment process. For more information regarding
MIC and its RQ adjustment, refer to the Technical
Background Document to Support Rulemaking
Pursuant to CERCLA Section 102, Volume 6. These
documents are available for inspection in the
Superfund Docket at U.S. EPA, 401 M Street, SW,
Washington, DC 20460. Telephone 202-260-3046
for more information.
NOTICE: This document is intended solely for informational purposes and cannot be relied upon to
create any rights enforceable by any party in litigation with the United States.
v>EFV\
United States
Environmental Protection
Agency (5202G)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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