Recently there has been discussion in the fire service regarding SCBA cylinder interchangeability. The International Association of Fire Chiefs (IAFC) has reached out to a number of organizations who are working on this issue, including NFPA, the InterAgency Board (IAB), and the National Institute for Occupational Safety and Health (NIOSH), so that we may clarify some of the issues and concerns in the community.

Exposure to high temperature environments may cause the loudness of PASS alarm signals to be reduced, potentially causing the alarm signal to become indistinguishable from background noise at the incident scene. This problem was brought to the attention of the NFPA Technical Committee on Electronic Safety Equipment by the National Institute for Occupational Safety and Health's (NIOSH) Fire Fighter Fatality Investigation and Prevention Program.

NIOSH reported that during the investigation of four fire fighter fatalities that occurred from 2001 to 2004, the PASS alarms were not heard or were barely audible. The PASS had been certified as compliant to NFPA 1982, Standard on Personal Alert Safety Systems (PASS), 1998 Edition, and involved both stand-alone PASS and SCBA-integrated PASS.