In the aftermath of the wildfires that stormed through both northern and southern California over the last two years, a new problem surfaced, one in which ECA members are going to be an important part of the solution.

The problem is benzene, a colorless, flavorless, sweet- smelling chemical that you have probably smelled when filling up your gas tank at a service station. Benzene is showing up in the water supplies of homes and businesses in areas that burned—Paradise and Del Oro for instance—where 2100 homes survived the fires that destroyed 18,800 other structures, killing 86 residents during the November 2018 Camp Fire.

Initial testing in Paradise found benzene as high as 923 parts per billion. In neighboring Del Oro, pipes on burned lots get tested before getting water connections the concentration was as high as 530 parts per billion. The State Water Resources Control Board (SWRCB) considers those numbers outliers, with some water showing nothing and most other samples coming in with readings of less than 20 parts per billion. This inconsistency is part of the problem.

One part per billion (ppb), which is California’s safety standard, is equal to one drop of water in an Olympicsized swimming pool. The state standard uses an estimate of “possible” ill effects on a person drinking two liters of water a day over 70 years with that 1 ppb contamination. The federal Environmental Protection Agency (EPA) standard is 5 ppb.

Something New

The issue first surfaced in Santa Rosa following the Tubbs Fire in October 2017 where 13 out of 500 homes tested showed high levels of benzene.

“That’s when we started realizing, wow, has this been happening before and nobody realized it?” said EPA toxicologist Bruce Macler, who is on loan to SWRCB, helping with fire response. “It could have happened in any house fire. There is still a lot of hypotheses, and we have not gotten the research to settle this.”

Wildfire temperatures reach 1,500o Fahrenheit plus, the melting point of many metals. That means the underground service pipes leading to the homes may need replacement, regardless of benzene. The Paradise Irrigation District is focusing on a plan to replace all lateral pipes that test positive for contamination. The cost estimate is $300 million, and the Federal Emergency Management Agency (FEMA) usually picks up the tab on municipal disaster repairs.

With our focus on “local,” when this issue surfaces in southern California wildfire areas, ECA members will be part of the solution.

By Dave Sorem, P.E., ECA Government Affairs Chairman Email: [email protected]