The facility has had many monkeys die accidentally: one of the first fatalities to be reported occurred in February 2002, when a monkey crawled into a drain pipe and was killed by an impeller.
A monkey completely escaped from the facility in 2003, leading many to question whether UC Davis was competent enough to handle a proposed bio-defense lab. The bio-defense lab, if created, would have infected monkeys with dangerous diseases such as anthrax and smallpox; an escaped monkey from the facility would have therefore posed a potential threat to the community (source). A higher level laboratory would have better security.
Outside the facility — but still part of the center's monkey population — seven (of eight in the room) long-tailed Macaque research monkeys died on August 21, 2004 of heat exhaustion after a heater malfunctioned. The temperature rose from its normal 75 degrees F. to 115 degrees F. The event occurred in the Animal Resources Science building south of campus, which served as an overflow facility for the Primate Center. After this happened the overflow facility was shut down.