Hidden Danger in Water Confronts California Wildfire Survivors

California’s 2018 Camp Fire was the deadliest blaze in state history. The fast-moving inferno burned 153,000 acres in Butte County, destroyed nearly 19,000 buildings, and caused the deaths of 86 people.

From all that destruction, a mysterious threat has emerged for those who appeared to have gotten by unscathed: household water supplies with concentrations of toxic benzene—including one sample that had 923 times what the state considers safe.

More than nine months after the fire, the Paradise Irrigation District still has a “do not drink” order unless individual parcels have been cleared. Even baths are discouraged, according ...