A Northern California community is still dealing with the aftermath of a November incident in which the Martinez Refining Company failed to notify the public of the release of toxic dust.

The accidental release of a “spent catalyst” from the refinery began the night on Nov. 24, 2022, and continued into the early hours of Nov. 25, showering the surrounding community of Martinez in 20 tons of metal-laden dust, health officials said.

As the dust release remains under investigation, the Contra Costa Health Department cautioned residents of the city east of San Francisco against eating produce grown in exposed gardens.

“Foods grown in soil that contains certain metals may pose health concerns – anyone who is growing food is encouraged to understand the make-up of their soil,” wrote the health department. “Until further environmental testing is complete, the health department recommends not eating foods grown in soil that may have been exposed to the spent catalyst.”

“Just this morning, a friend of mine was asking me about gardening advice, and she wants to plant a garden with her young children,” said Heidi Taylor, whose garden full of produce was blanketed by some of the 20 tons of dust. “Oh my god, don’t put it in the soil. The first thing I said to her was, you better have a container. This is container gardening time now because of what they did.”

County Public Health Director Dr. Ori Tzvieli said a toxicologist will be hired to review the data the health department and hazmat team collect throughout the month.

“We’re looking basically to see if there’s evidence of contamination, where it is, how deep it is and if yes, what needs to be done to remediate the situation. So, until we know, we really recommend not eating food grown in soil that’s been exposed to the spent catalyst,” said Tzvieli.

The dust doesn’t just pose a health threat through the soil – the white powder could have created breathing and respiratory impacts for Martinez residents exposed to it back in November.

The long-term health impacts are “difficult to ascertain at this time,” the health department said.

The Martinez Refining Company did not notify health officials about the release, leading the county to consider enforcement action against the company. The public health department’s investigation into the November incident has been turned over to the district attorney’s office for review.

Taylor said she is considering planting certain flowers that can help pull toxins out of the soil. She is concerned about throwing the dirt away for fear of potentially contaminating a landfill.

The Martinez Refining Company has notified Contra Costa Health Services of upcoming maintenance at its facility. It will cause flaring that can be seen from the surrounding area through Monday.

This story originally reported by KTLA sister station KRON.