How did Exide happen?

And can state and local environmental agencies ensure that it never happens again?

Jbefore battery recycler Exide Technologies planned to reopen its troubled Vernon plant, the company agreed Wednesday to permanently shut it down rather than face federal criminal prosecution for decades of environmental crimes. The deal with the U.S. attorney’s office requires Exide to close and demolish the plant and decontaminate the site, as well as fund the cleanup in surrounding neighborhoods.

This is good news for nearby residents who had worried the company would reopen and resume its pattern of air pollution and hazardous-waste violations. At the peak of its operations, Exide took in 40,000 lead-acid vehicle batteries a day. The batteries were crushed and the primary components — acid, lead and plastic — were processed, washed or smelted for recycling. It’s extremely dirty work that Exide was allowed to perform for 30 years on a temporary permit without adequate, modern environmental and health protections, and despite repeated enforcement actions and penalties.

As a result, the company tainted the groundwater and polluted the soil on its site with lead, arsenic and other toxic metals. It trucked shipments of crushed plastic that leaked battery acid and lead onto roads. Worse, the pollution spread to surrounding residential neighborhoods, where regulators found such high levels of lead that they warned parents not to let their kids play in their yards. Lead is a neurotoxin that can cause children to develop learning disabilities and behavioral problems. Some 115 homes must have contaminated soil removed and replaced, and dozens more have yet to be tested.

Although the agreement with the Department of Justice is an important step toward cleaning up the community, it does not answer the central questions: How was a company allowed to operate for so long with so many violations that endangered so many people? And has the state done enough to ensure this never happens again?

The state and local agencies responsible for regulating hazardous waste, water pollution and air quality failed for years to address the public health risks posed by Exide’s operations. The state’s Department of Toxic Substances Control allowed Exide to stay open on a temporary permit for three decades. It took the federal government’s intervention to shut the company down and guarantee the cleanup.

The department’s new director, Barbara Lee, said at a state Senate hearing Thursday that she is committed to reforming the agency and protecting communities near hazardous-waste facilities. But the work of reversing decades of poor coordination among regulators and lax enforcement will require more than the promise of one director. Gov. Jerry Brown and state legislators must provide leadership and demand accountability. California may have some of the most protective environmental laws in the nation, but they are meaningless if not enforced.