SOUTH LAKE TAHOE (AP) — Officials at a South Lake Tahoe resort say they fired three employees who improperly drained 15,000 to 20,000 gallons of chlorinated pool water into a storm-water basin.

State environmental regulators said they started an investigation last month after the Lake Tahoe Vacation Resort self-reported the June 25 incident.

Alan Miller, senior water resource control engineer for the California Regional Water Quality Control Board, said there doesn’t appear to have been any immediate environmental impact. He said it’s unlikely the resort will face fines because it has taken internal steps to prevent similar incidents.

“It’s definitely something we would not authorize because of the chlorine, which is toxic to aquatic life,” Miller told The Tahoe Daily Tribune. “What they did was not proper. At the same time, their remedies may be sufficient.”

The resort near Ski Run Marina is part of Diamond Resorts International, a publicly traded resort chain based in Las Vegas.

Benjamin La Luzerne, a lawyer for the parent company, said the resort fired three workers and has agreed to create a pool drainage management plan to ensure its pool is properly drained in the future.

“As a company, we understand the sensitive nature of the Lake Tahoe environment,” La Luzerne said.

“Unfortunately, we had three employees that chose not to follow the standard procedure of draining the pool into the proper drains. We have terminated those employees and are retraining the rest of the staff responsible for maintaining the pool to ensure that it does not happen again,” he said.

Jason Burke, storm-water program coordinator for South Lake Tahoe, said he saw no evidence of chlorine-killed plants when he investigated the infiltration basin several days after the incident.

“The thing I will credit them with, they did report this themselves, which they are required to do,” Burke said.

The infiltration basin is located along a bike path through the area, which is considered a stream environment zone by the Tahoe Regional Planning Agency.

The agency is continuing to investigate the incident to make sure there was no damage to the zone, said Julie Regan, its chief of external affairs.