The Overview

If you live near an industrial site in California, a new state law just changed what can be built next door to your home. A new California law bars cities and counties from approving a building permit for a new reactive chemical storage facility with explosion potential unless it has a backup cooling or other contingency system approved by the local unified program agency and is not adjacent to a home. California's SB 883 hazardous materials law became law when Gov. Gavin Newsom (D) signed it Sept. 27. ​

A tank holding about 7,000 gallons of methyl methacrylate at a Garden Grove aerospace plant began failing in May 2026, prompting evacuations of about 50,000 people and nearly causing a major incident, according to the Los Angeles Times. At the time, 14 California facilities stored the same reactive chemical, according to CalMatters. The bill became law on September 27, 2026, when the Secretary of State chaptered it as Chapter 658, Statutes of 2026.

What the Law Does

Cities and counties can no longer approve a building permit for a new reactive chemical storage facility with explosion potential unless the site has a backup cooling or contingency system approved by the local hazardous materials agency and is not built next to a home. Before approving such a permit, a city council or county board of supervisors must give the public notice and a chance to comment, then notify the Office of Emergency Services and the Office of Environmental Health Hazard Assessment.

The law adds methyl methacrylate to California's accidental release prevention program, requiring facilities storing it above a threshold quantity to file a risk management plan; the state must set that threshold through regulation, and no facility storing the chemical may be exempted. Local hazardous materials agencies must inspect each reactive chemical storage facility at least once every three years and report results to state environmental and emergency agencies. Existing sites, including GKN Aerospace, are exempt from the new facility requirements, according to CalMatters.

Legislative Status

Sen. Tom Umberg, a Democrat, is the bill's lead author, and Bennett and Connolly are its coauthors. The Senate passed it 37-0 on April 23. The Assembly passed it 63-13 on Aug. 31, and the Senate concurred in Assembly amendments 38-0 the same day. Umberg said the law "addresses the gaps this incident exposed and puts stronger protections in place to keep our communities safe."

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