BAY POINT — State health and Navy experts will speak at a public forum that aims to update residents on allegations that potentially radioactive soil was dumped at Keller Canyon Landfill.

The forum is scheduled for Thursday at the Ambrose Community Center and aims to answer questions about the soil shipped from the Hunters Point Naval Shipyard in San Francisco to the Keller Canyon Landfill outside Pittsburg.

Experts from the Radiologic Health Branch of the California Department of Public Health, the U.S. Navy and the San Francisco Bay Area Regional Water Quality Control Board will be at the forum to answer any questions.

Allegations over falsified data and samples at the Hunter’s Point Superfund site go back years, but recent developments have thrust the issue back into the spotlight. The former shipyard hosted the Naval Radiological Defense Laboratory, which decontaminated ships that were exposed during atomic weapons tests and also researched the effects of radiation.

Whistleblowers claimed the Navy contractor Tetra Tech falsified data on the levels of radioactivity in the soil, but it wasn’t until a joint report from the Environmental Protection Agency, Department of Toxic Substances Control and California Department of Public Health report came out in April that the level of fraud began to become public.

The report stated that 90 to 97 percent of soil samples re-tested by the three agencies were “neither reliable nor defensible.” The report was not released by the three agencies, but was obtained through a Freedom of Information Act Request from the watchdog group Public Employees for Environmental Responsibility.

In early May, two former Tetra Tech supervisors pleaded guilty to falsifying soil samples in federal court and each was sentenced to eight months in prison.

Between 2011 and 2017, Keller Canyon accepted 223,000 tons of material from Hunter’s Point that was certified as nonhazardous under 13 separate waste applications, according to Marilyn Underwood, the county’s director of environmental health.

On two occasions — once in June 2014 and once on February 18, 2015 — soil and material shipped to Keller Canyon had to be returned to Hunter’s Point.

In 2014, a facility inspection by the county noted that “soil from Hunter’s Point with slightly elevated lead content was accidentally brought into the facility.”

In the 2015 incident, CDPH was notified of the potential hazard after an anonymous complaint was filed with a health physicist in the Radiological Health Branch. The anonymous person stated that nine truckloads of asphalt had been shipped from Hunters Point to Keller Canyon “without having been surveyed and cleared for radioactive contamination.”

CDPH staff went out to the site and found that the nine truckloads were giving off radiation levels that were above “but very close to background levels” and that they had been shipped out without being surveyed or cleared for removal, according to Dale Schornack, public affairs officer for CDPH.

They later determined that six fist to foot-sized pieces of asphalt showed non-hazardous levels of Cesium-137, a radioactive isotope, Schornack wrote in an email to this newspaper.

According to a summary of the event written by county health officials, they were notified by CDPH on the same day. They wrote that the asphalt was being stored for analysis by Tetra Tech, but was accidentally sent out by a contractor. The material did not trigger radiation sensors at either Hunters Point or Keller Canyon.

The return of nine truckloads of radioactive asphalt was not mentioned by county health officials in their Feb. 23, 2015, inspection report filed with CalRecycle.

The forum will start at 6:30 p.m. on Thursday at the Ambrose Community Center, 3105 Willow Pass Road in Bay Point.