More than 8,300 blazes have scorched four million acres (and counting) in California this wildfire season—doubling the state’s previous record, set just two years ago. In addition to their rising frequency and severity, such fires are increasingly burning through residential areas throughout the West. This trend not only presents immediate dangers to the people living there but can have toxic consequences for the local water supply that can persist long after the smoke clears.
“Most people are not aware that when there are major wildfires, there is often some pretty serious water contamination,” says Erik Olson, NRDC’s senior strategic director for public health issues.
A study recently published in the journal AWWA Water Science found toxins, such as benzene and other volatile organic compounds, in the water distribution networks of areas hit by the Tubbs and Camp wildfires in 2017 and 2018, respectively.
The Camp Fire burned through California’s Butte County, destroying 18,800 homes and buildings and killing 86 people. In its aftermath, water samples in the Paradise Irrigation District showed benzene levels at 2,217 parts per billion (ppb). The federal limit for this cancer-causing compound in drinking water is just 5 ppb, and the legal limit in California is even lower at 1 ppb.
Other volatile organic compounds including naphthalene, toluene, and styrene were also present at levels exceeding federal safety standards, putting residents at risk for conditions ranging from irritated skin and nausea to more serious issues affecting the nervous, immune, and reproductive systems and impaired development in children. Further, long-term exposure to some of these chemicals, such as benzene, naphthalene, and styrene, are known or suspected to cause cancer.
Water loaded with mud and debris churns across a wash in an area of Zuma Canyon burned by the 2018 Woolsey Fire.
Since 80 percent of the country’s freshwater supply originates on forestland, and thousands of communities rely on public water systems located in forested watersheds, anticipating various threats to water quality during and after wildfires is essential to protecting public health.
The Safe Drinking Water Act requires states to develop emergency drinking water plans for natural disasters. But “the plans are not as detailed as they need to be and are often not tested and not effective,” says Olson. “With climate change, we’re going to see more and more wildfires, and if we don’t have emergency water plans, people will be left high and dry.”
