SPARKS, Nev. (AP) – A drug research company says a roomful of research monkeys quarantined at its lab in Sparks, Nev., were accidentally killed in May due to overheating.

Officials for Massachusetts-based Charles River Laboratories issued a statement Thursday confirming that 32 longtail macaques died at its Sparks lab. The company blames a series of human error in the operation of climate control in one room at the quarantine facility. It says the May 28 incident affected no other primates and that at no point was the public ever in danger. The monkeys were to be used in drug research.

The company says it reported the incident immediately to the U.S. Department of Agriculture and the Centers for Disease Control and Prevention.

AP-ES-08-07-08 1912EDT