California likes to pat itself on the back for being a leader in protecting the environment.

Every year, California workers dig up hundreds of thousands of tons of soil contaminated with things like lead, petroleum hydrocarbons and chemicals like DDT. The waste is so toxic, California considers it to be hazardous and requires that it be disposed of at a facility specially designed to handle such dangerous material.

Or, at least, that would be the requirement if the waste stayed in California. It often doesn’t.

A CalMatters investigation found that, for decades, California businesses and government agencies have taken hazardous waste over the border and dumped it at regular landfills in states with weaker environmental regulations.

Among the findings:

• Much of the waste is going to landfills in Arizona and Utah with fewer safeguards and less oversight than permitted hazardous waste disposal facilities.
• Two of the most popular destinations are next to Native American reservations. One of those landfills has a spotty environmental history, Arizona records show.
• One of the biggest out-of-state dumpers is the state’s own Department of Toxic Substances Control which, since 2018, took more than 105,000 tons of lead-contaminated soil from the area around the Exide cleanup in Los Angeles County and disposed of it in Arizona. Most went to a landfill that Arizona regulators labeled in 2021 an “imminent and substantial threat.”

CalMatters reporter Robert Lewis and photo editor Miguel Gutierrez traveled to Arizona and Utah, documenting where much of the Golden State’s toxic waste ends up. The Department of Toxic Substances Control said its decision to take the waste to Arizona is driven by cost and acknowledged the agency doesn’t really know how the out-of-state landfills are managed. Gov. Gavin Newsom’s office wouldn’t comment.

David Harper, a member of the Colorado River Indian Tribes, questioned why the Golden State would dump its toxic waste so close to the reservation, which straddles the border between California and Arizona.

• Harper: “If it was not a problem, why didn’t they keep it themselves? Why does it have to come here? Why isn’t it in California?”