CHARLESTON, W.Va. (AP) – Tests found decay and other problems in emergency air packs carried by state mine inspectors, prompting West Virginia officials on Thursday to issue an alert warning all of the state’s underground coal operations.

The SR100 air packs were manufactured in 1998 by Monroeville, Pa.-based CSE, before the company began installing a heat damage indicator on each air pack, according to the state Office of Miners’ Health Safety and Training.

Since mine inspectors store their air packs in their vehicles, “it is possible that the extreme heat frequently generated inside parked vehicles has contributed to the damage,” Terry Farley, administrator of enforcement, wrote in a memo to coal operators and independent contracts.

Farley said oxygen starting cartridges in all nine air packs failed, which would delay the production of enough oxygen to sustain life by 15 to 20 minutes.

Farley said the state will attempt to determine how many CSE SR100 units lacking heat damage indicators are in use in West Virginia’s mines and are being stored in vehicles, equipment or surface facilities. Once the survey is complete, the state will order mine operators to immediately remove from service all such units.