"We are making this recommendation out of an abundance of caution," said Dr. Ori Tzvieli, health officer for Contra Costa County, who issued the health advisory Tuesday. "There is no immediate health threat to the community. That said, it's also always better to be safe than sorry."
With the spring growing season starting, Tzvieli said refinery neighbors in Martinez and Pacheco can safely plant seeds now in their yards and gardens.
But he cautioned residents to wait for the results of environmental testing before eating anything grown in soils exposed to the spent catalyst. Testing results are expected in the late spring or early summer.
VIDEO: More than 7 tons of contaminated soil, 1M gallons of water evacuated from Ohio train derailment site
Contaminated soil, water evacuated from Ohio train derailment site
The refinery released more than 20 tons of metal-laden dust into the community over Thanksgiving weekend.
The accidental release of "spent catalyst" started around 9:30 p.m. Nov. 24 and continued into the early hours of Nov. 25, showering the surrounding community in the dust-like substance.
Samples of the dust later showed elevated levels of aluminum, barium, chromium, nickel, vanadium, and zinc, all of which could have caused respiratory problems in people breathing it.
County policy required MRC to alert the community via the county emergency system and to immediately notify the county health department, neither of which happened.
County health officials said they learned about the release via media reports a day and a half later. The county is investigating the release and has referred the case to the Contra Costa County District Attorney's Office. Refinery officials have said they're cooperating with the investigations.
An oversight committee formed to investigate the chemical release will hold its second virtual meeting Thursday.
For those still concerned about gardening in potentially contaminated ground soil, Tzvieli said people can choose to safely grow produce in pots, planters or raised garden beds using fresh soil.