Exposure limits of volatile, organic/petroleum-based solvents, widely used in the industrial field, have been determined to control their use due to their toxic and deformation-causing effects. The excretion of solvents from the body after exposure is mostly through the urine by undergoing biotransformation. The metabolites formed as a product of biotransformation is used as biomarkers to determine the exposure levels of solvents.

Because of their toxicity, the exposure of toluene, xylene, and styrene found in petroleum derivatives, cigarette smoke and insulting materials is delimitated by Occupational Safety and Health Administration (OSHA). The acute toxicologic effects of toluene, xylene, and styrene mostly affect the central nervous system and cause symptoms like weakness, dizziness, memory loss and nausea. However, their chronic toxicological effects can cause permanent brain damage, organ failure, paralysis, coma and even death. Also, styrene is classified as group II which is a potential carcinogen type, by International Agency Research on Cancer (IARC). Hippuric acid is identified as the biomarker of toluene, methyl hippuric acid is identified as the biomarker of xylene, mandelic acid and phenylglioxylic acid are identified as the biomarkers of styrene.