Skin/Eye Contact
Benzene splashed in the eyes can result in pain and corneal injury. Repeated or prolonged skin contact with liquid benzene can degrease the skin, causing it to crack and peel. Percutaneous absorption is slow through intact skin; however, benzene absorbed through the skin may contribute to systemic toxicity.
Children are more vulnerable to toxicants absorbed through the skin because of their larger surface area:weight ratio.
Ingestion
Acute toxic effects can result from ingestion of benzene. A burning sensation of the oral mucous membranes, esophagus, and stomach may occur after ingestion. Nausea, vomiting, and abdominal pain may also result from oral ingestion.
Sources/Uses
Benzene is the 17th most abundantly produced chemical in the United States. It is obtained primarily from crude petroleum. Benzene is used mainly as a raw material for synthesizing chemicals such as styrene, phenol, and cyclohexane and for manufacturing dyes, detergents, explosives, rubber, plastics, and pharmaceuticals. It is found in trace amounts in cigarette smoke and drinking water, as a contaminant in some industrial solvents, and as a constituent of motor fuels, unleaded gasoline in particular.
Standards and Guidelines
OSHA PEL (permissible exposure limit) = 1 ppm (averaged over an 8-hour workshift).
OSHA STEL (short-term exposure limit) = 5 ppm (15-minute sample).
NIOSH IDLH (immediately dangerous to life or health) = 500 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) = 150 ppm.
Physical Properties
Description: Clear, colorless-to-light-yellow liquid
Warning properties: Sweet solvent odor at 1.5 to 5 ppm. Adequate warning for acute exposure; inadequate for chronic exposure as olfactory fatigue can occur.
Molecular weight: 78.1 daltons
Boiling point (760 mm Hg): 176¡ãF (80.1¡ãC)
Freezing point: 41.9¡ãF (5.5¡ãC)
Specific gravity: 0.88 (water = 1)
Vapor pressure: 75 mm Hg at 68¡ãF (20¡ãC)
Gas density: 2.8 (air = 1)
Water solubility: Slightly water soluble (0.07% at 68¡ãF) (20¡ãC)
Flammability: Flammable at temperatures ~12¡ãF (-11¡ãC)
Flammable range: 1.2 to 7.8% (concentration in air).
Incompatibilities
Benzene reacts explosively with strong oxidizers, such as perchlorates and nitric acid, and many fluorides.