They are technical in nature and can be extremely dangerous to first responders ... There are a couple of things about placarding on which I have disagreed with DOT for many years.

Placards identify the hazard classes while labels do the same for smaller packages and containers, according to the department of transportation. The 25 types of placards and 29 types of labels ...

A Department of Transportation (DOT ... hazardous material in your vehicle that requires your vehicle to have a placard. Drive a vehicle on the interstate with a gross combination weight rating ...