ELYRIA, Ohio (AP) -- Columbus Gas says it is shutting off the gas for about 2,500 residents in Elyria due to a problem discovered during a routine maintenance check.

The company discovered air in a gas line Thursday afternoon, and says it is shutting off the gas flow as a precaution in affected areas. The company says residents are safe and crews will visit each affected customer to conduct a home safety inspection.

The mayor's office says affected customers will be without gas for between 24 and 48 hours.

Elyria City Schools canceled classes Friday because of the shut-off. The American Red Cross has also opened a shelter for residents.

The Elyria Fire Department is urging residents not to use auxiliary heating methods during the outage.