You're prepping a tractor that will pull a placarded load of Class 3 gasoline. The only fire extinguisher on board is one you grabbed from your personal car — it's labeled 1-A:5-B:C. Does this extinguisher satisfy the federal requirement for this placarded power unit?

49 CFR 393.95(a)(1)(i)

Most fire extinguishers people buy for a car or garage are rated well below what the law requires for a placarded truck, so grabbing "any" extinguisher off a shelf can leave you out of compliance without realizing it. A 10 B:C extinguisher has roughly double the flammable-liquid/electrical-fire capacity of a typical small consumer unit, which matters because hazmat fires involve larger fuel volumes than a car engine fire. Carrying an undersized extinguisher is also a roadside inspection violation that can put your truck out of service.