What you Should know about the ACGIH's Threshold for nPB Solvents

If you work with industrial chemicals, materials or solvents then you may have heard of the American Conference of Governmental Industrial Hygienists (ACGIH). The ACGIH is a scientific, but non-governmental body of industrial hygienists that publishes Threshold Limit Value (TLV) opinions on chemicals such as n-propyl bromide. These TLV opinions are not held to the same standards as limits set by an organization such as OSHA, but are still published in books available on the ACGIH website. You or someone else in your company might be familiar with these TLVs.

In March 2014, the ACGIH published a new TLV for n-propyl bromide (1-bromopropane). This TLV was set at 0.1ppm, and refers to “commercial grade bromopropane (99% 1-BP with 0.1%-0.2% 2-bromopropane).” 2-bromopropane is also known as isopropyl bromide (iPB). In addition to this TLV opinion, the flash point for nPB is listed as 21 degrees Celsius by ACGIH, when it is commonly known throughout the industry and proven in numerous studies that nPB has no flash point. Modern nPB manufacturing processes result in nPB with <0.01% iPB contamination, which is of a pharmaceutical quality.

The 1-BP properties referenced by the ACGIH rely to some degree on information first published in 1999 and 2000, which contains information that is out of date and inaccurate when referring to today’s purity of 1-BP. Some things to keep in mind regarding ACGIH TLV opinions include:

  • TLVs are not determined by speaking openly with scientific experts, but in closed-door meetings.
  • There is no scientific consensus backing up ACGIH’s findings.
  • ACGIH TLV opinions may involve conflicts of interest and uncertain science.
  • The ACGIH is a not-for-profit organization that funds its activities by selling books; it is not a government-sanctioned panel of experts.

The IBSA et al. v. ACGIH lawsuit documents a number of these concerns involving the ACGIH and how they determine their TLV opinions. There is nothing worse than misinformation in our field – not only are safer chemicals such as nPB made to seem dangerous, but chemicals that are unsafe or unsuitable might be seen as acceptable alternatives. Enviro Tech urges you and others in your company not to rely solely on TLVs, but rather on official and informed sources instead (See US EPA SNAP Approval for 1-BP). For more information on the properties of nPB and related solvents, please contact Enviro Tech today.