2020 Emergency Response Guidebook ERG United States Government DOT Department of Transportation PHMSA's 2020 Emergency Response Guidebook (ERG) provides first responders with a go-to manual to help deal with hazmat transportation accidents during the critical first 30 minutes. DOT's goal is to place an ERG in every public emergency service vehicle nationwide. It is a guidebook intended for use by first responders during the initial phase of a transportation incident involving dangerous goods or hazardous materials.