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Following a months-long investigation, Laguna Beach police announced Thursday that an employee accidentally over-chlorinated a pool that left 17 sea lions sick at the Pacific Marine Mammal Center in April.

filephoto Sea Lion
File photo of sea lion (Credit: Alejandro Hernandez/flicker via Creative Commons)

Employees at the center arrived on April 28 to find the sea lions were suffering from varying degrees of corneal ulcerations after swimming in one of the pools.

Police were called when the employees determined pool had been contaminated with an excessive amount of chlorine.

Initially, employees felt an intruder may have entered the facility and intentionally contaminated the pool.

“The chlorine incident — very sad, because they didn’t ask for it. They didn’t ask for any of this. They had already been near death when they came into the center for the first time, and they got all the way through that … and then someone came in and did this horrific incident,” Keith Matassa of the Pacific Marine Mammal Center said. “All they wanted to do was get back out to the wild.”

During the investigation, detectives focused on employees, volunteers, former employees, the cleaning crew, pool maintenance staff and witnesses in the area after learning the person responsible must have had a very good working knowledge of the filtration system, a news release from the Police Department stated.

More than a dozen sea lions that were sickened by chlorine poisoning in April at a Laguna Beach facility were released back into the ocean on June 2, 2015. (Credit: KTLA)
More than a dozen sea lions that were sickened by chlorine poisoning in April at a Laguna Beach facility were released back into the ocean on June 2, 2015. (Credit: KTLA)

Upon reviewing the information, detectives determined the pool was accidentally over-chlorinated, with no criminal intent, by an employee who had access to the machinery operating the filtration system.

The employee was apparently unaware of the mishap or the cause, according to the news release.

“This unfortunate incident lead to an exhaustive investigation, but in the end, we are pleased to report that all seventeen sea lions have recovered from their injuries,” the Police Department stated in the news release.

“We can also attest to the good work the Pacific Marine Mammal Center and its employees are doing to save the lives of endangered sea lions off our coasts,” the news release read.

In front of a large crowd of spectators on June 2, 14 of the sea lions were released back into the ocean in Laguna Beach.