Authorities in Southern California have lifted the final evacuation orders for residents living near a damaged chemical tank in Garden Grove, allowing approximately 16,000 people to return home after nearly a week of disruption. The evacuation, which began on May 22, impacted around 50,000 residents in and around the Orange County city.

The tank, containing 6,000 to 7,000 gallons of methyl methacrylate—a highly flammable chemical used by GKN Aerospace Transparency Systems in the manufacture of cockpit windows and windshields—developed a crack that facilitated pressure release, preventing a potential explosion. Officials confirmed the tank’s temperature stabilized after cooling efforts, including sprinkler activation and removal of tank insulation, and remained steady for four hours without intervention, prompting the lifting of evacuation orders.

Orange County Fire Authority Division Chief Craig Covey reported that a failure in a valve on the tank’s cooling system caused the interior temperature to rise to 100 degrees Fahrenheit over the weekend before being brought down to 92 degrees. Fire crews worked to neutralize two nearby tanks to ensure containment and safety.

Despite assurances from health officials that no chemical contamination or fumes were released, residents expressed concern at a city council meeting held after the evacuation orders were lifted. Several attendees questioned the presence of such hazardous materials in a densely populated area and demanded accountability from both the local government and the company operating the tank.

Karen Nguyen, a Garden Grove resident, voiced apprehension about the chemical’s effects on her pets and community, calling for stricter regulations to prevent future incidents. Another resident, Bobbi-Lee Smart, highlighted the company’s history of regulatory violations and urged authorities to take decisive action to protect residents, many of whom lacked the means to evacuate.

Mayor Stephanie Klopfenstein assured the public that efforts would be made to hold the company responsible. Earlier, GKN Aerospace issued a statement apologizing for the disruption and reaffirming cooperation with authorities, emphasizing safety as their top priority. In 2025, GKN agreed to pay over $900,000 in settlements related to violations including recordkeeping, permitting, and nitrogen oxide emissions, according to state environmental reports.

Orange County Health Director Regina Chinsio-Kwong encouraged returning residents to feel confident about their safety, noting ongoing monitoring plans. Isabel Mendez, a resident who experienced temporary symptoms such as rash and throat irritation during the evacuation, said her symptoms resolved shortly after leaving the area.

Moving forward, the South Coast Air Quality Management District will conduct air quality monitoring for several months, while the Environmental Protection Agency will test local sewer and storm drain systems for any chemical contamination. Orange County Supervisor Janet Nguyen emphasized that officials remain vigilant in ensuring community safety following the incident.