Potential uses of petrochemical products can result in significant benzene exposures: MSDSs must list benzene as an ingredient.

According to 29 CFR1910.1200 (Hazard Communication Standard [HCS]), a material safety data sheet (MSDS) must list a carcinogen as an ingredient if its concentration in a product is 0.1% or more by weight. However, according to the HCS, when the concentration of a carcinogen in a product is less than 0.1% (by weight) it may not be necessary to list it as an ingredient on the MSDS. The standard stipulates that if potential uses of the product can result in exposures to the carcinogen that exceed the Occupational Safety and Health Administration (OSHA) permissible exposure limit or the ACGIH threshold limit value (TLV), then it must be listed. This article focuses on the failure of MSDSs to report benzene as a listed ingredient in products that incorporate petroleum-derived ingredients such as toluene and hexane. In the United States, approximately 238,000 people are occupationally exposed to benzene each year. Only rarely is benzene listed as an ingredient on MSDSs even though it often comprises more than 0.1% of petroleum solvents and, when its concentrations in petroleum-derived products are much less than 0.1%, inhalation exposures to benzene can be much higher that its OSHA PEL of one part per million (ppm) by volume (v/v) andACGIH TLV of/one-half ppm (v/v). As a consequence of benzene's omission from MSDSs as a listed ingredient, employers are frequently unaware of their requirement to implement 29 CFR 1910.1028 (Benzene Standard) and of the need to address employee exposures to benzene in the workplace. This article demonstrates that benzene should be listed as an ingredient on MSDSs, even at concentrations in benzene-containing products that are between one and two orders of magnitude below OSHA's 0.1% threshold. An exposure assessment methodology is presented that is applicable to employees whose conditions of exposure are similar to those in the published study. These workers make up a similar exposure group. The information and methodology presented here are germane to preparation of accurate MSDSs for benzene-containing products, employers who must comply with 29 CFR 1910.1028, and retrospectively estimating exposures to benzene.