Police discovered yesterday that a man and his 10-year-old daughter died early Sunday morning of carbon monoxide poisoning in his College Township apartment.

The State College Police Department responded twice to the requests of two different family members to check on the welfare of Andrew J. Heckman, 43, of 2158 Mountainview Ave., and his daughter, Abigail Yeagley, of 531 Westview Ave.

Police had responded to the first call shortly after midnight yesterday but no one answered Heckman's door. Police were unable to gain entry into the apartment.

Sgt. John Gardner said the apartment smelled strongly of natural gas and that he had difficulty breathing when he entered the residence at 11:38 a.m. yesterday.

Police contacted the owner of the rental property, who let police into the residence.

Police believe the toxic levels of carbon monoxide were caused by the faulty heating system of the four-apartment building Heckman lived in. Heckman's apartment was the closest to the faulty heating system.

Heckman and Yeagley were the apartment's only occupants.

Police did not disclose where their bodies were found in Heckman's apartment.

The Centre County Coroner's Office, the Centre Region Code Administration, Alpha Fire Co. and Columbia Gas Co. are working together to investigate the incident, police said.

Police have not yet focused their investigation on answering who might be responsible for the deaths, Gardner said.

Rob Boulware, spokesman for Columbia Gas Co., said if a furnace is burning improperly, it can release carbon monoxide, a colorless, odorless gas that is deadly when inhaled.

Gardner said people living in homes that use gas heating should make sure they have working carbon monoxide detectors.

People using gas appliances should have them checked and maintained on a regular basis, Boulware said. Owners should follow the advice listed on their products and become educated about natural gas use, he added.

Information about natural gas can be found at www.columbiagas.com.