You notice a strange odor near your trailer after a hard brake application. You suspect a hazmat package might be leaking, but you're not sure which one or what it is. What's the correct way to handle identifying the leaking material?

AAMVA CDL Manual Sec 9.7.3 (nhcdm.pdf p.9-16)

Some hazardous vapors can injure or kill at concentrations you can't smell, or they damage your sense of smell on first exposure, so "smell testing" a leak gives false confidence instead of real information. Shipping papers and package placement tell you what's almost certainly leaking without requiring you to get close enough to be exposed. Relying on paperwork, not your senses, is central to keeping hazmat drivers safe during an unplanned release.