HERCULES — A Hercules lab worker allegedly put a living rabbit in a freezer earlier this year, an apparent violation of the federal animal welfare law, according to the U.S. Department of Agriculture.

An Aug. 19 USDA inspection of Pacific Biolabs uncovered internal records at the testing laboratory, showing that lab workers attempted to euthanize the rabbit and placed it in a carcass freezer, but the rabbit was not dead.

The USDA did not cite the facility, but required the company to take steps to ensure the incident will not be repeated. An animal rights group, however, is asking the USDA to issue $10,000 fine against Pacific Biolabs, the maximum fine for a violation of the Animal Welfare Act.

“It speaks of a very high level of incompetence when a laboratory can”t even kill an animal correctly,” said Michael Budkie, co-founder and executive director of Stop Animal Exploitation Now. “We are talking about a situation where the staff at biolabs weren”t able to tell if the animal was alive or dead … what does that say about their ability to do anything scientific?”

A company spokesman did not immediately return a call for comment. The lab, located at 551 Linus Pauling Drive, is a research facility for the pharmaceutical, biotech, and medical device industries, according to its website.

In 2013, Pacific Biolabs used 4,233 rabbits, 5,030 guinea pigs, 66 hamsters, 16 dogs and 16 pigs to conduct research and testing, according to its annual report filed with the federal government. Ten of those rabbits and four of those guinea pigs underwent painful or distressful testing without anesthesia because it would have affected results, the report said.

David DeBolt covers breaking news. Contact him at 510-262-2728. Follow him at Twitter.com/daviddebolt.