DOWNTOWN LOS ANGELES (CBSLA.com) — A Los Angeles city councilman is trying to get to the bottom of how the Dockweiler State Beach area became inundated with plastic medical waste last month.

“It was absolutely horrifying,” councilman Mike Bonin said during a news conference at City Hall Tuesday. “People took their children down to their beaches and found condoms, tampon containers and syringes.”

The waste washed up on Sept. 23, prompting officials to close Dockweiler, Manhattan and Marina del Rey beaches for up to four days.

Bonin says he’s worried this could happen again when the expected El Nino storms sweep into the Southland.

As of now, the L.A. County Department of Sanitation suspects recent storms dislodged a plastic build-up from a one-mile-long pipe at the Hyperion Water Reclamation Plant. The pipe, recently put back into use, may not have been sufficiently cleaned after a sewage spill in 2004. Some say the city should revert back to using a five-mile pipe that has been closed for maintenance work.

Bonin suspects someone may have even intentionally dumped the waste. He has ordered the sanitation department to look into the cause and possible preventative measures, and report back in 21 days.

Heal the Bay president Alix Hobbs spoke alongside Bonin and described the state of those beaches affected by the spill as “truly something that harkens back to the ’90s.”

“We have not seen this in the numerous cleanups that we’ve done at Heal the Bay for over 20 years,” Hobbs said. “So to find this on our beaches is really an assault.”

Additionally, the Regional Water Quality Control Board is doing a more detailed investigation, according to Heal the Bay’s science and policy director Rita Kampalath. Those findings are expected to be released in January.

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