On March 13, 2013 (78 FR 16045), the Pipeline and Hazardous Materials Safety Administration (PHMSA) published a safety notice advising the public that PHMSA has confirmed the unauthorized marking, service and/or sale of certain high pressure Department of Transportation (DOT) specification cylinders marked with a requalification identification number (RIN) without performing a valid hydrostatic requalification test. Approximately 496 DOT 3AA and 3AL cylinders used in carbon dioxide service were improperly marked from approximately June 2010 to December 2012. Cylinders subject to this notice were serviced or purchased from Flint Welding Supply Co, Flint, MI and were marked with an “A978” or a partial “A978” or just the Month/Year, without a RIN mark in the middle. Kraus Fire Equipment Co. requalified cylinders provided by Flint Welding Supply Co. without performing the series of safety tests and inspections required by the Hazardous Materials Regulations. These improperly marked cylinders were not properly tested and may not possess the structural integrity to safely contain their contents under pressure during normal transportation and use. Extensive property damage, serious personal injury, or death could result from a rupture of a cylinder. These cylinders should be considered unsafe and unauthorized for the filling of hazardous material unless and until they are first tested properly by an individual or company authorized by DOT to requalify DOT specification cylinders. Cylinders described in this safety advisory that are filled with an atmospheric gas should be vented or otherwise safely discharged by authorized personnel. Individuals who identify a cylinder subject to this notice are advised to remove it from service and return it to Flint Welding Supply Co, Flint MI.