High levels of carbon monoxide at a Delaware County supermarket sent three people to a local hospital as a precaution.

Police and fire units were called about 7 a.m. yesterday to the Super Fresh in the Manoa Shopping Center in Havertown. Store employees had alerted officials after carbon monoxide detectors had sounded, police said.

Medical units checked 26 people for exposure. The source of the gas was a malfunctioning fan in the store's bakery area.

This was the second time in seven months that the store had experienced problems with elevated levels of carbon monoxide from the fan. In August, 31 people were taken to seven area hospitals after exposure. Calls to Super Fresh were not returned. - Mari A. Schaefer