Olin Chlorine Leak Injures 4; Prompts Shelter-in-Place in Clute & Lake Jackson

Just after 9:00 a.m. on May 20, 2025, a shelter-in-place order was issued for Brazosport ISD, Brazosport College, and parts of Lake Jackson and Clute, Texas, due to a chlorine gas release at Olin Plant B.

Brazosport CAER reported the chlorine leak at 9:01 a.m. at Olin Corporation’s Plant B inside the vast Dow-owned Texas Operations complex along the Brazos River. Olin’s on-site team activated Level 3 protocols (gas confirmed beyond the facility). Local fire and hazmat crews staged at perimeter roads while plant personnel isolated the source.

By 9:46 a.m. Olin reported the release had been stopped, but shelter orders remained in place until officials could confirm air monitoring readings. 

Four workers, all members of the International Union of Operating Engineers, were treated for injuries related to the chlorine release. Three were released, and a fourth was hospitalized.

As of 10:40 a.m., the shelter-in-place order was lifted. The cause of the chlorine leak has not yet been determined.

About the Facility & Its Operator

Olin, a nearly 130-year-old chemical producer headquartered in Missouri, bought Dow’s chlor-alkali assets at Freeport/Lake Jackson in 2015. The site makes chlorine, caustic soda, and epoxy-grade derivatives used in everything from PVC pipe to household cleaners.

Chlorine production involves high-pressure, corrosive processes—leaks can occur at flanges, valves, or loading lines if preventive maintenance slips or if operators bypass alarms to keep throughput high.

Why Chlorine Gas Is So Dangerous

At room temperature, chlorine is a green-yellow gas that is heavier than air and moves close to the ground. Low-level exposure can irritate the eyes, nose, and throat within seconds. Moderate concentrations trigger coughing, chest tightness, and shortness of breath. High concentrations cause rapid lung injury, chemical pneumonitis, and can be fatal without immediate medical care.

Because wind shifts and temperature changes can push chlorine gas in unpredictable directions, shelter-in-place orders are a necessary precaution to protect nearby communities in the event of a release.

How to Shelter in Place for a Chlorine Release

• Get Inside, Quickly: Pick an interior room with the fewest windows.
• Seal the Envelope: Shut doors, windows, and fireplace dampers; stuff towels around gaps; turn off fans, HVAC, and window units.
• Monitor Official Channels: Follow local emergency management Facebook/Twitter, NOAA Weather Radio, or reverse 911 calls.
• Stay Put: Remain inside until authorities announce “all clear.”
• If Exposed: Move to fresh air, remove contaminated clothing, rinse eyes/skin with water for 15 minutes, and seek medical attention if you feel throat or chest irritation.

We’ll be following the details of this Olin chlorine leak as they’re released. Our thoughts are with the workers and residents affected by this incident.