DOT' Federal Motor Carrier Safety Administration (FMCSA) strives to improve road safety as it relates to the transport of hazardous materials. To learn more, visit FMCSA's hazmat-related website.
The Federal Aviation Administration (FAA) is in charge of regulating, certifying and enforcing hazardous materials transportation for U.S. private and commercial air transportation. Learn more at the FAA's Office of Hazardous Materials Safety.
The Maritime Administration's (MARAD) mission is to support a healthy and robust U.S. maritime transportation industry. They have plenty of helpful information for first responders on the MARAD website.