A symbol or "M Number" is issued to a company as a means of identification. Under certain regulations, the M number must be used solely as the identifier on a package, for example DOT 39 nonrefillable cylinders, 49 CFR 178.65(i)(2). However, other regulations allow the manufacturer to use either the symbol or their name and address as specificed in 49 CFR 178.3(a)(2). Lists of manufacturer's symbols are in two formats. The first format lists the manufacturers sequentially by Identification Number (M #). The second format lists each state's manufacturers alphabetically by city and company name. The identification number, the name and address, the status and the date of the registration are provided in both formats.

Manufacturer's Symbols by Identification Number

State Listing (Alphabetical PDF files)