PHMSA is issuing this safety advisory notice to inform the public, industrial gas stakeholders, and relevant government officials of the risks associated with re-qualifying, filling, and transporting cylinders bearing the DOT specification markings ‘‘DOT 4E’’ or ‘‘DOT 4BA’’ that were produced by a company located in Thailand by the name of Metal Mate. Metal Mate does not have an approval from PHMSA to manufacture cylinders to DOT specifications; therefore, cylinders marked with the Metal Mate name are not DOT specification cylinders. These cylinders are to be considered fraudulent and should not be filled.