The record number and severity of wildfires in California this year and in years past have exposed a previously rare and little-known problem: benzene and other contaminants leaching into the water supply from burned and damaged infrastructure, often at extremely toxic levels.
After the Tubbs Fire swept through parts of Napa, Sonoma, and Lake counties in October 2017, residents of Santa Rosa and other badly damaged cities found their tap water had a noxious chemical odor much like diesel fuel. Similar problems turned up in other fire-damaged parts of California.
Benzene exposure and cancer
Water tests conducted by environmental and health officials found that the tap water in Santa Rosa, for instance, was heavily laden with benzene, a colorless chemical that can cause life-threatening cancers and other diseases, including Acute Myeloid Leukemia (AML), Myelodysplastic Syndrome (MDS), lymphomas and aplastic Anemia.
Investigations of the water contamination threat in parts of California impacted by wildfires indicate that heat from the fires can cause benzene and other chemicals in plastic pipes to leach into the water supply.
Some studies also found that damaged, depressurized water systems can suck wildfire smoke and pollutants from the air into the pipes, distributing contaminated water to residents with functioning taps.
In some cases, flushing the system with fresh water can lower the amount of benzene to levels considered safe for humans. In other cases, layer upon layer of toxic compounds have accumulated in the infrastructure, forcing authorities to replace the pipes, hydrants and meters.
According to STAT News, benzene levels as high as 40,000 parts per billion were recorded after the 2017 Tubbs Fire and as high as 2,217 parts per billion following the 2019 Camp Fire. The U.S. Environmental Protection Agency (EPA) considers 5 parts per billion to be the maximum level of benzene safe for humans. In California, environmental regulators have set that threshold to just one part per billion.
As the wildfires continue to rage through parts of central and northern California, fears of further water contamination problems across the state have increased.
Testing is often tricky and imperfect, too. Many agencies use benzene levels as the benchmark for water pollution, but water that tests low for benzene may contain dangerously high levels of naphthalene, styrene, methylene chloride, and other carcinogenic chemicals.
“Nobody has actually figured out which compounds are of most consequence,” Andrew Whelton, an associate professor of civil, environmental and ecological engineering at Purdue University, told STAT. “In the case of Camp Fire, for instance, Paradise Irrigation District sometimes found benzene at levels that didn’t pose a risk, but other chemicals were there that did.”
Professor Whelton told STAT that regulators should put fire-damaged water systems under a blanket “do not use” order because it’s the only way to keep consumers safe amid all the variation and uncertainty.
In some places, residents return home to “do not drink/do not boil” warnings. Warnings often include recommendations to limit showering time, avoid using warm or hot water, and to ventilate the showering area to reduce the risk of exposure to benzene and possibly other chemicals.
Rethinking water infrastructure
All of this has officials in California, Oregon and Washington worried about water contamination problems in the future as wildfires triggered by global warming threaten to become increasingly more common, bigger, and more intense.
The threat will likely force engineers and regulators to reimagine the water distribution systems in areas at high risk of fire damage.
Beasley Allen lawyers in our Toxic Torts Section work to protect people and property from toxic chemicals and environmental pollution. Beasley Allen lawyer John Tomlinson investigates claims of cancer related to benzene exposure,