Revisions to Spacecraft Maximum Allowable Concentrations for 2-Butanone.

As part of a periodic review of historical limits, SMACs were revised for all durations for 2-butanone. Acute SMACs were increased from 50 ppm to 200 ppm. The SMAC for 7 d was increased from 10 ppm to 67 ppm, and the SMACs for 30 and 180 d were increased from 10 ppm to 22 ppm. A SMAC for 1000 d has now been set at 22 ppm. Limits based on the most recent evidence and risk assessment methodologies will ensure the appropriate degree of conservatism in future spacecraft design. Ryder VE. Revisions to spacecraft maximum allowable concentrations for 2-butanone. Aerosp Med Hum Perform. 2025; 96(12):1094-1097.