New toluene diisocyanate (TDI) occupational exposure limits adopted by the ACGIH

Pittsburgh, February 2, 2016 — The American Conference of Governmental Industrial Hygienists (ACGIH®) has adopted new time-weighted average (TWA) and short-term exposure limit (STEL) Threshold Limit Values (TLVs®) for Toluene-2,4 or 2,6-diisocyanate or as a mixture (TDI).  These adopted values lower the 8-hour TWA from 5 parts per billion (ppb) to 1 ppb and the 15-min STEL from 20 ppb to 5 ppb. ACGIH also adopted a biological exposure index (BEI®) of 5 μg/g creatinine.

ACGIH® is a private, not-for-profit, nongovernmental corporation that publishes guidelines known as TLVs® and BEIs®.  ACGIH® acknowledges that these guidelines are not regulatory 'standards.' The Occupational Safety and Health Administration (OSHA) does have a standard, or a US regulatory exposure limit for TDI, which is set at 20 ppb (Ceiling limit for 2,4-TDI). This OSHA exposure limit is the only US regulatory occupational exposure limit for TDI.

The newly adopted ACGIH® values will be published in the 2016 TLVs® and BEIs® Book. The TLV® and BEI® Documentation will became available to the public around mid-March 2016. For more information about this change, please visit www.acgih.org. Additional information about TDI can be found on the Diisocyanates Panel website www.americanchemistry.com/dii and the Center for the Polyurethanes Industry’s website www.americanchemistry.com/.