The discovery was as surprising as it was ominous. Weeks after the Camp Fire roared through Butte County last November, devouring entire towns, officials made an alarming find: The Paradise drinking water is now laced with benzene, a volatile compound linked to cancer. Water officials say they believe the extreme heat of the firestorm created a “toxic cocktail” of gases in burning homes that got sucked into the water pipes when the system depressurized from use by residents and firefighters.