Appendix B to Subpart C of Part 197 - Substance Technical Guidelines, Benzene
46:7.0.1.5.30.3.75.18.2 : Appendix B
Appendix B to Subpart C of Part 197 - Substance Technical
Guidelines, Benzene I. Physical and Chemical Data
(a) Substance identification. (1) Synonyms: Benzol,
benzole, coal naphtha, cyclohexatriene, phene, phenyl hydride,
pyrobenzol. (Benzin, petroleum benzin, and benzine do not contain
benzene).
(2) Formula: C6 H6 (CAS Registry Number: 71-43-2).
(b) Physical data. (1) Boiling point (760 mm Hg): 80.1 °C
(176 °F).
(2) Specific gravity (water = 1): 0.879.
(3) Vapor density (air = 1): 2.7.
(4) Melting point: 5.5 °C (42 °F).
(5) Vapor pressure at 20 °C (68 °F): 75 mm Hg.
(6) Solubility in water: .06%.
(7) Evaporation rate (ether = 1): 2.8.
(8) Appearance and odor: Clear, colorless liquid with a
distinctive sweet odor.
II. Fire, Explosion, and Reactivity Hazard Data
(a) Fire. (1) Flash point (closed cup): −11 °C (12
°F).
(2) Autoignition temperature: 580 °C (1076 °F).
(3) Flammable limits in air, % by volume: Lower: 1.3%, Upper:
7.5%.
(4) Extinguishing media: Carbon dioxide, dry chemical, or
foam.
(5) Special fire fighting procedures: Do not use a solid stream
of water, because it will scatter and spread the fire. Fine water
spray may be used to keep fire-exposed containers cool.
(6) Unusual fire and explosion hazards: Benzene is a flammable
liquid. Its vapors can form explosive mixtures. All ignition
sources must be controlled when benzene is used, handled, or
stored. Areas where liquid or vapor may be released are considered
hazardous locations. Benzene vapors are heavier than air. Thus,
benzene vapors may travel along the deck and ground and be ignited
by open flames or sparks at locations remote from the site at which
benzene is handled.
(7) Benzene is classified as a flammable liquid for the purpose
of conforming to the requirements of 49 CFR 172.101 concerning the
designation of materials as hazardous materials. Locations where
benzene may be present in quantities sufficient to produce
explosive or ignitable mixtures are considered Class I Group D
locations for the purposes of conforming to the requirements of 46
CFR parts 30 through 40, 151, and 153 when determining the
requirements for electrical equipment as specified in Subchapter J
(Electrical engineering).
(b) Reactivity. (1) Conditions contributing to
instability: Heat.
(2) Incompatibility: Heat and oxidizing materials.
(3) Hazardous decomposition products: Toxic gases and vapors
(such as carbon monoxide).
III. Spill and Leak Procedures
(a) Steps to be taken if the material is released or
spilled. As much benzene as possible should be absorbed with
suitable materials, such as dry sand or earth. That remaining must
be flushed with large amounts of water. Do not flush benzene into a
confined space, such as a sewer, because of explosion danger.
Remove all ignition sources. Ventilate enclosed places.
(b) Waste disposal method. Disposal methods must conform
to state and local regulations. If allowed, benzene may be disposed
of (a) by absorbing it in dry sand or earth and disposing in a
sanitary landfill, (b), if in small quantities, by removing it to a
safe location away from buildings or other combustible sources or
by pouring onto dry sand or earth and cautiously igniting it, and
(c), if in large quantities, by atomizing it in a suitable
combustion chamber.