A massive oil merger is about to happen in California—and taxpayers could be on the hook for billions

A new state law mandates that oil companies put up money to plug wells before acquiring them. It could fail its first big test, putting taxpayers on the hook.

In recent years, California has passed new laws to tackle the enormously expensive remediation of old oil wells, which pose hazards for human health and the climate. But as two of the state’s largest oil well operators race toward a corporate merger, the challenge of holding companies accountable for their mess is coming into view.