LAWRENCEVILLE, GA., JULY 30 -- Fourteen research monkeys died of heat stroke after being left outside as temperatures here soared into the 90s, the U.S. Centers for Disease Control said today.

The rhesus monkeys, which had been taken from their cages for deworming and health screening, were discovered on the floor of an outdoor housing building at the agency's breeding and holding complex here.

The monkeys died July 9, but the CDC made the first public announcement today. Officials said it was the largest number of accidental primate deaths in the agency's history. The monkeys were among a colony of 100 raised for research in the CDC's breeding complex.

Researchers said heat usually doesn't cause abnormal stress for rhesus monkeys, which are commonly found in the subtropical regions of India and Asia, as well as in the frigid Himalayas of Nepal.

"Everyone concerned with it is very upset that it happened, and we are taking steps to see that it doesn't happen again," said Bobby G. Brown, chief of the CDC's animal resources branch.

Brown said the monkeys, among 33 taken from one section of the rhesus compound, had been anesthetized to allow animal handlers to safely deworm them and test them for the simian AIDS virus and tuberculosis. The other monkeys suffered no ill effects.