Southern California Edison was set to release 19,200 gallons of “non-radiological and radiological” liquids a mile offshore today, Dec. 19, from the San Onofre Nuclear Generating site.

The four- to six-hour process takes place regularly, Edison said, but has raised concern among surfers who ride waves at nearby San Onofre State Beach.

Discharges, which include non-radiological and radiological releases, are made 1.1 miles offshore of San Onofre, according to Surfrider Foundation, which fought earlier this year to have such activity made public.

“The goal is to keep the local beach-going and surf community informed about what effluent and potential hazards are posed by actions at the local nuclear plant,” the nonprofit posted in a statement on its website. “Now at least you can know before you go.”

Here’s more from Surfrider:

“Edison explains that the effluent has been treated to a radiological dose level of just 0.00183 mrem (millirem), which is 0.0321% of the annual whole body dose limit.

“Surprisingly, this is well within their legal allowance set by the Nuclear Regulatory Commission (NRC), which has a maximum annual dose limit from liquid effluent of 3 mrem per unit. While batch releases have occurred since the plant first became operational, this is the first time the public has been notified in advance, consistent with our effort to have Edison increase transparency and public knowledge of the plant’s actions,” the statement reads.

The storage of nuclear waste has been hotly debated for years, with concerns raised by activists about failing canisters that can seep into the water; what would happen to cooling pools and stored canisters in the event of a major earthquake; and the impending danger of sea level rise and erosion to the beach.

Southern California Edison says the storage is safe inside its “concrete monolith,” and the $4.4 billion process to tear down the two large power plant domes gained approval from the California Coastal Commission in October, along with spent fuel pools and the remainder of the nuclear plant.

The wastewater release notice from Edison was posted Dec. 17, two days before the release, on its Liquid Batch Release Notification page:

“Like any industrial site, San Onofre has permits to discharge operational wastewater into the ocean. These discharges include non-radiological and radiological releases,” the notice reads.

“The non-radiological releases, such as sewage, meet the stringent criteria of our National Discharge Pollutant Elimination System permit, as implemented by the State Water Resources Control Board. SCE’s license with the Nuclear Regulatory Commission governs radiological releases. In both cases, the wastewater is cleaned-up and highly diluted before release to the ocean via discharge ports that are more than a mile offshore from San Onofre.

“SCE has been safely cleaning and discharging these liquids for more than 50 years with no measurable impact on the environment. When San Onofre was operating, these were done frequently, sometimes daily. With the shutdown of the plant, they have dropped dramatically.”