The Associated Press

BLACKSBURG, Va. — Two Virginia Tech students were in critical condition and 15 other people were hospitalized Sunday after a suspected carbon monoxide leak at an apartment complex, police said.

The two women were flown to the University of Virginia Medical Center and their three roommates were flown to Duke University Medical Center in Durham, N.C., after being found unresponsive in their beds in the Collegiate Suites apartment complex, police Capt. Bruce Bradbery said. All five women are students.

Two of the women flown to Duke could breathe on their own but remained unresponsive, Bradbery said; he described the other as semiconscious. All three were in serious condition, authorities said.

Twelve others were taken to Montgomery Regional Hospital in Blacksburg, where they were in stable condition, hospital spokeswoman Suzanne Barnette said. At least four others were treated on the scene.

A resident of a nearby apartment had gotten sick and called the gas company, thinking there was a gas leak, Bradbery said. The employee realized it wasn't a gas leak and called police shortly after 11 a.m.

Readings taken by the Blacksburg Fire Department before noon showed carbon monoxide levels of 500 parts per million in the apartment shared by the five women, Bradbery said. People experience symptoms of carbon monoxide poisoning at levels as low as 25 parts per million, he said.

The apartment complex was evacuated, and police were investigating.

The apparent leak came the same day Virginia Tech dedicated a memorial to the 32 people killed by a student gunman in April. Fall semester classes begin Monday.