by Dian Cucchisi, PHD, CHMM
The Clean Air Act, finalized originally in 1970, was amended in 1990 in an effort to reduce mobile source pollution. Included in this amendment was the directive to phase out chemicals that were identified as “ozone depleting”. For those in the metal-working industry this meant the phase out of a very popular vapor degreasing chemical (1,1,1 Trichloroethane) by 1996.
As the phase-out deadline approached, industries scrambled to find a suitable replacement for solvents like 1,1,1 Trichloroethane. For vapor degreasing, the solvents that were known to work well included methylene chloride and trichloroethylene. Use of methylene chloride or trichloroethylene was not a popular option as both solvents have low permissible exposure limits (PEL), are suspected human carcinogens, and are regulated for air emissions, shipping, and disposal.
The chemical industry produced several potential alternatives for metal cleaning including aqueous cleaning solutions and some new solvents. Aqueous cleaning solutions were not a viable alternative for most metal-working shops due to the spotting that remained after the parts were dried. Many of these metal-working shops produced parts for the electronics industry and spotting could not be tolerated.
N-Propyl Bromide (NPB) (also known as 1-bromopropane) emerged as one of the most popular alternative solvents for metal cleaning. As it emerged on the market it was described as a “safety solvent”. The term safety solvent was used because the chemical was not regulated for shipping or disposal and the Occupational Safety and Health Administration (OSHA) had not issued a PEL for this chemical. The solvent has a very strong odor which provided an incentive for companies to implement some controls to keep the vapors out of the workplace. However, without regulatory guidance, the effectiveness of the controls was determined by what was considered an acceptable level of odor in the workplace.
On July 31, 2013 OSHA issued a Hazard Alert titled “OSHA and NIOSH issue hazard alert on 1-bromopropane, urge efforts to safeguard workers from exposure to toxic chemical”
"The use of 1-bromopropane has increased in workplaces over the last 20 years," said Dr. David Michaels, Assistant Secretary Of Labor for Occupational Safety And Health. "Workers exposed to this toxic chemical can suffer serious health effects, even long after exposure has ended. Hazardous exposure to 1-BP must be prevented. Employers have a responsibility to ensure the safety of their workers." Exposure to 1-BP has been associated with damage to the nervous system among workers, and it has been shown to cause reproductive harm in animal studies. The chemical is used in degreasing operations, furniture manufacturing, and dry cleaning. The hazard alert was issued in response to information on the increased use of 1-BP as a substitute for other solvents as well as recent reports of overexposure in furniture manufacturing. 1-BP was nominated as a chemical of concern in OSHA's Web Forum to Identify Hazardous Chemicals.
The chemical industry works continually to meet the demands of their users and as a result, chemical substances are produced at a fairly rapid rate. There are approximately 87,000 chemicals used in industry with less than 1,000 regulated for use, shipping, and disposal. Physical and health hazard testing takes time—initial health hazard testing can provide information on acute effects but can only speculate on chronic effects. In addition, the U.S. Federal government may determine that there is not enough scientific data to support regulating the chemical for use, shipping, or disposal. As a result, new chemical substances are introduced into the marketplace without sufficient information for worker and environmental protection.
Environmental, Health and Safety professionals utilize many resources to aid them in determining measures for worker and environmental protection. Although regulations may not be able to keep up with the rate at which new chemicals are introduced into the marketplace, we have access to information and tools for measuring that can be used for recommending controls. Just because a chemical is not regulated by OSHA, EPA, or the DOT, does not mean that the chemical is “safe”.