• Part Number:
  • Part Number Title:
    Occupational Safety and Health Standards
  • Subpart:
    1910 Subpart Z
  • Subpart Title:
    Toxic and Hazardous Substances
  • Standard Number:
  • Title:
    Substance Technical Guidelines for 1,3-Butadiene (Non-Mandatory)
  • GPO Source:
I. Physical and Chemical Data

 A. Substance identification:

 1. Synonyms: 1,3-Butadiene (BD); butadiene; biethylene; bivinyl;
divinyl; butadiene-1,3; buta-1,3-diene; erythrene; NCI-C50620;
 2. Formula: CH(2)=CH-CH=CH(2).
 3. Molecular weight: 54.1.

 B. Physical data:

 1. Boiling point (760 mm Hg): -4.7 deg. C (23.5 deg. F).
 2. Specific gravity (water=1): 0.62 at 20 deg. C (68 deg. F).
 3. Vapor density (air=1 at boiling point of BD): 1.87.
 4. Vapor pressure at 20 deg. C (68 deg. F): 910 mm Hg.
 5. Solubility in water, g/100 g water at 20 deg. C (68 deg. F):
 6. Appearance and odor: Colorless, flammable gas with a mildly
aromatic odor. Liquefied BD is a colorless liquid with a mildly
aromatic odor.

II. Fire, Explosion, and Reactivity Hazard Data

 A. Fire:

 1. Flash point: -76 deg. C (-105 deg. F) for take out; liquefied
BD; Not applicable to BD gas.
 2. Stability: A stabilizer is added to the monomer to inhibit
formation of polymer during storage. Forms explosive peroxides in air
in absence of inhibitor.
 3. Flammable limits in air, percent by volume: Lower: 2.0; Upper:
 4. Extinguishing media: Carbon dioxide for small fires, polymer or
alcohol foams for large fires.
 5. Special fire fighting procedures: Fight fire from protected
location or maximum possible distance. Stop flow of gas before
extinguishing fire. Use water spray to keep fire-exposed cylinders
 6. Unusual fire and explosion hazards: BD vapors are heavier than
air and may travel to a source of ignition and flash back. Closed
containers may rupture violently when heated.
 7. For purposes of compliance with the requirements of 29 CFR
1910.106, BD is classified as a flammable gas. For example, 7,500
ppm, approximately one-fourth of the lower flammable limit, would be
considered to pose a potential fire and explosion hazard.
 8. For purposes of compliance with 29 CFR 1910.155, BD is
classified as a Class B fire hazard.
 9. For purposes of compliance with 29 CFR 1910.307, locations
classified as hazardous due to the presence of BD shall be Class I.

 B. Reactivity:

 1. Conditions contributing to instability: Heat. Peroxides are
formed when inhibitor concentration is not maintained at proper
level. At elevated temperatures, such as in fire conditions,
polymerization may take place.
 2. Incompatibilities: Contact with strong oxidizing agents may
cause fires and explosions. The contacting of crude BD (not BD
monomer) with copper and copper alloys may cause formations of
explosive copper compounds.
 3. Hazardous decomposition products: Toxic gases (such as carbon
monoxide) may be released in a fire involving BD.
 4. Special precautions: BD will attack some forms of plastics,
rubber, and coatings. BD in storage should be checked for proper
inhibitor content, for self-polymerization, and for formation of
peroxides when in contact with air and iron. Piping carrying BD may
become plugged by formation of rubbery polymer.

 C. Warning Properties:

 1. Odor Threshold: An odor threshold of 0.45 ppm has been reported
in The American Industrial Hygiene Association (AIHA) Report, Odor
Thresholds for Chemicals with Established Occupational Health
Standards. (Ex. 32-28C)
 2. Eye Irritation Level: Workers exposed to vapors of BD
(concentration or purity unspecified) have complained of irritation
of eyes, nasal passages, throat, and lungs. Dogs and rabbits exposed
experimentally to as much as 6700 ppm for 7 1/2 hours a day for 8
months have developed no histologically demonstrable abnormality of
the eyes.
 3. Evaluation of Warning Properties: Since the mean odor threshold
is about half of the 1 ppm PEL, and more than 10-fold below the 5 ppm
STEL, most wearers of air purifying respirators should still be able
to detect breakthrough before a significant overexposure to BD

III. Spill, Leak, and Disposal Procedures

 A. Persons not wearing protective equipment and clothing should be
restricted from areas of spills or leaks until cleanup has been
completed. If BD is spilled or leaked, the following steps should be

 1. Eliminate all ignition sources.
 2. Ventilate areas of spill or leak.
 3. If in liquid form, for small quantities, allow to evaporate in a
safe manner.
 4. Stop or control the leak if this can be done without risk. If
source of leak is a cylinder and the leak cannot be stopped in place,
remove the leaking cylinder to a safe place and repair the leak or
allow the cylinder to empty.

 B. Disposal: This substance, when discarded or disposed of, is a
hazardous waste according to Federal regulations (40 CFR part 261).
It is listed by the EPA as hazardous waste number D001 due to its
ignitability. The transportation, storage, treatment, and disposal of
this waste material must be conducted in compliance with 40 CFR parts
262, 263, 264, 268 and 270. Disposal can occur only in properly
permitted facilities. Check state and local regulations for any
additional requirements because these may be more restrictive than
federal laws and regulations.

IV. Monitoring and Measurement Procedures

 A. Exposure above the Permissible Exposure Limit (8-hr TWA) or
Short-Term Exposure Limit (STEL):

 1. 8-hr TWA exposure evaluation: Measurements taken for the purpose
of determining employee exposure under this standard are best taken
with consecutive samples covering the full shift. Air samples must be
taken in the employee's breathing zone (air that would most nearly
represent that inhaled by the employee).
 2. STEL exposure evaluation: Measurements must represent 15 minute
exposures associated with operations most likely to exceed the STEL
in each job and on each shift.
 3. Monitoring frequencies: Table 1 gives various exposure scenarios
and their required monitoring frequencies, as required by the final
standard for occupational exposure to butadiene.

   Table 1. -- Five Exposure Scenarios and Their Associated
                       Monitoring Frequencies

Action    8-hr
 level     TWA    STEL            Required monitoring activity

   -(*)     -       -   No 8-hr TWA or STEL monitoring required.

   +(*)     -       -   No STEL monitoring required. Monitor 8-hr
                         TWA annually.

   +        +       -   No STEL monitoring required. Periodic
                         monitoring 8-hr TWA, in accordance with

   +        +       +   Periodic monitoring 8-hr TWA, in
                         accordance with (d)(3)(ii)(**).

                        Periodic monitoring STEL, in accordance
                         with (d)(3)(iii).

   +        -       +   Periodic monitoring STEL, in accordance
                         with (d)(3)(iii). Monitor 8-hr TWA,
 Footnote(*) Exposure Scenario, Limit Exceeded: + = Yes, - = No.
 Footnote(**) The employer may decrease the frequency of exposure
monitoring to annually when at least 2 consecutive measurements taken
at least 7 days apart show exposures to be below the 8 hr TWA, but at
or above the action level.

 4. Monitoring techniques: Appendix D describes the validated method
of sampling and analysis which has been tested by OSHA for use with
BD. The employer has the obligation of selecting a monitoring method
which meets the accuracy and precision requirements of the standard
under his or her unique field conditions. The standard requires that
the method of monitoring must be accurate, to a 95 percent confidence
level, to plus or minus 25 percent for concentrations of BD at or
above 1 ppm, and to plus or minus 35 percent for concentrations below
1 ppm.

V. Personal Protective Equipment

 A. Employees should be provided with and required to use impervious
clothing, gloves, face shields (eight-inch minimum), and other
appropriate protective clothing necessary to prevent the skin from
becoming frozen from contact with liquid BD.
 B. Any clothing which becomes wet with liquid BD should be removed
immediately and not re-worn until the butadiene has evaporated.
 C. Employees should be provided with and required to use splash
proof safety goggles where liquid BD may contact the eyes.

VI. Housekeeping and Hygiene Facilities

 For purposes of complying with 29 CFR 1910.141, the following items
should be emphasized:

 A. The workplace should be kept clean, orderly, and in a sanitary
 B. Adequate washing facilities with hot and cold water are to be
provided and maintained in a sanitary condition.

VII. Additional Precautions

 A. Store BD in tightly closed containers in a cool, well-ventilated
area and take all necessary precautions to avoid any explosion
 B. Non-sparking tools must be used to open and close metal
containers. These containers must be effectively grounded.
 C. Do not incinerate BD cartridges, tanks or other containers.
 D. Employers must advise employees of all areas and operations
where exposure to BD might occur.

[61 FR 56746, Nov. 4, 1996]