Subpart Z
No — under 1910.1028 App B, "Benzin," "petroleum benzin," and "Benzine" do not necessarily contain benzene; the appendix specifically states these names do not contain benzene while listing other synonyms that do (for example, benzol, benzole, coal naphtha). See Substance identification in 1910.1028 App B.
Under 1910.1028 App B, benzene has a closed-cup flash point of −11 °C (12 °F) and flammable limits in air by volume of Lower: 1.3% and Upper: 7.5%, which matters because mixtures within that range can ignite and create a fire or explosion hazard. Employers must treat benzene as a flammable liquid and control ignition sources; see Flammability data in 1910.1028 App B and the general flammable liquids requirements at 1910.106.
Under 1910.1028 App B, "heavier than air" means benzene vapors can travel along the ground and collect in low areas, and therefore employers must control ignition sources at and beyond the immediate handling area and provide ventilation to prevent vapor buildup. See Vapor behavior and hazard in 1910.1028 App B and electrical/classification guidance at 1910.309.
Under 1910.1028 App B, use carbon dioxide, dry chemical, or foam on benzene fires and avoid a solid stream of water because it can scatter and spread the flame; a fine water spray may be used to cool exposed containers. See Extinguishing media and fire-fighting procedures in 1910.1028 App B and general requirements for flammable liquids at 1910.106.
Under 1910.1028 App B, a workplace should be considered a Class I, Group D hazardous location when benzene may be present in quantities sufficient to produce explosive or ignitable mixtures; that classification aligns with the electrical requirements in 1910.309. See Fire and explosion hazards in 1910.1028 App B.
Under 1910.1028 App B, a benzene concentration exceeding 3,250 ppm is considered a potential fire/explosion hazard. Employers must control ignition sources and handle such atmospheres as hazardous; see Unusual fire and explosion hazards in 1910.1028 App B and consult 1910.106 for flammable liquid storage and handling.
Under 1910.1028 App B, immediately absorb as much benzene as possible with suitable material such as dry sand or earth, remove all ignition sources, ventilate enclosed places, and avoid flushing benzene into confined spaces or sewers because of explosion danger. See Spill and leak procedures in 1910.1028 App B.
No — under 1910.1028 App B you must not flush benzene into confined spaces such as sewers because that creates an explosion danger. The appendix advises absorbent cleanup, ventilation, and removal of ignition sources instead; see Spill guidance in 1910.1028 App B.
Under 1910.1028 App B, disposal methods must conform to applicable jurisdictional regulations; if allowed, benzene can be absorbed in dry sand or earth and placed in a sanitary landfill, small quantities can be removed and cautiously ignited in dry sand away from buildings, and large quantities can be atomized and burned in a suitable combustion chamber. See Waste disposal method in 1910.1028 App B.
Under 1910.1028 App B, transfers should be well ventilated and use good work practices to avoid spills; employers should also ground and bond containers and use non-sparking tools when opening or pouring. See Precautions for transfer and tools in 1910.1028 App B.
Under 1910.1028 App B, non-sparking tools and grounding/bonding prevent static or impact sparks that could ignite benzene vapors during opening and pouring operations. The appendix explicitly recommends this practice; see Miscellaneous precautions in 1910.1028 App B and consult 1910.106 for related flammable liquid handling.
Under 1910.1028 App B, operations with potential for high benzene exposure include the primary production and utilization of benzene and transfer operations (for example, pouring or charging), and employers must advise employees of plant areas and operations where exposure could occur. See Miscellaneous precautions and common operations in 1910.1028 App B.
Under 1910.1028 App B, benzene's boiling point is about 80.1 °C (176 °F) and its vapor pressure at 20 °C (68 °F) is 75 mm Hg, which implies benzene volatilizes readily at room temperature and can generate significant vapor concentrations that require ventilation and vapor control. See Physical data in 1910.1028 App B.
Under 1910.1028 App B, the appendix recommends good work practices such as using non-sparking tools and grounding/bonding containers, providing ventilation during transfers, and advising employees of areas where benzene exposure could occur; employers must implement controls and safe procedures in those operations. See Precautions and worker notification in 1910.1028 App B.
Under 1910.1028 App B, benzene is a clear, colorless liquid with a distinctive sweet odor; however, reliance on odor alone is unsafe because odor detection varies by person and benzene can be hazardous at concentrations below the level where odor is noticeable. See Appearance and odor in 1910.1028 App B.
Under 1910.1028 App B, benzene is incompatible with strong oxidizing materials and heat, and hazardous decomposition can produce toxic gases and vapors such as carbon monoxide; avoid mixing with oxidizers and control heat sources. See Reactivity and incompatibility in 1910.1028 App B.
Under 1910.1028 App B, benzene has an evaporation rate of about 2.8 (ether = 1) and very low solubility in water (~0.06%), so benzene evaporates relatively quickly and will not dissolve into water meaning spills should be contained and absorbed rather than flushed into drains; see Physical properties and spill guidance in 1910.1028 App B.
Under 1910.1028 App B, benzene's autoignition temperature is about 580 °C (1076 °F), which means while that is a high temperature, employers still must control lower-temperature ignition sources (sparks, open flames, hot surfaces) because benzene can ignite well below its autoignition temperature when mixed with air. See Autoignition temperature and fire hazards in 1910.1028 App B and general flammable liquid controls at 1910.106.
Under 1910.1028 App B, the appendix recommends ventilating enclosed places where benzene may be released and removing ignition sources; ventilation helps prevent vapor accumulation since benzene vapor can travel and collect in low areas. See Spill response and ventilation in 1910.1028 App B.