According to Lt. Mike Becker, hazmat coordinator for the Longmont (Colo.) Fire Department, decon boils down to two types: definitive and non-definitive.

Key procedures Becker recommends are:

• Identify the contaminants or agents you’re dealing with to gain better control of the incident.
• If the contaminant is known, chose the proper detection equipment or test approach to monitor the area and verify decontamination effectiveness.
• When the chemical is not known, standard decon procedures that assume a “worse-case scenario” get implemented.

“During the decontamination process, can you actually see a reduction in the contamination level?” Becker asked. “If you can meter or monitor or test for it, it’s something you can definitively check for and verify decontamination. If you don’t know what it is and cannot detect it, then it’s declared non-definitive and ALARA (as low as reasonable achievable) takes precedence. That’s when you need to plan on doing a thorough standard decon, including meticulously washing equipment, suits and things of that nature.”