County ends voluntary evacuation of Port Neches, the second since last week's plant explosion

The city of Port Neches and Jefferson County lifted a voluntary evacuation order Thursday afternoon, less than 24 hours after residents who were displaced for days last week amid a fire and multiple explosions at a local chemical plant were again asked to leave their homes Wednesday night.

The voluntary evacuation order was issued "out of an abundance of caution," according to a statement the county sent out at 10 p.m. Before the order, the city's 13,000 residents had been advised to shelter in place.

"It is recommended you leave the area as quickly and safely as possible as a protective action," the statement said.

Early Thursday afternoon, the Jefferson County Office of Emergency Management said that the shelter-in-place and evacuation orders were lifted due to improved conditions. The office said staff had been working to stop leaks that contributed to elevated levels of 1,3 butadiene, an extremely flammable, colorless gas often used to make rubber. It is one of the main chemicals produced at the plant owned by Houston-based TPC Group, where a fire broke out last week — the day before Thanksgiving — that sparked two major explosions and burned for more than a week.

"As a result of the actions taken, the levels have now been greatly reduced to non-irritating amounts," the office said in a Facebook post. "Air monitoring will continue to ensure the levels are being maintained at their current measurements."

The evacuation order was issued because winds and high humidity in the area were expected to keep vapors near the ground, according to the Port Neches Police Department.

"The current levels being measured do not pose a serious health risk but may cause dizziness, nausea, headaches, irritated eyes and throat," the department said in Facebook post late Wednesday night.​​​​​​

Earlier Thursday morning, the department said that air monitoring showed butadiene levels had decreased overnight but that the voluntary evacuation remained in effect. The shelter-in-place order also remained in effect, according to the county emergency management office. The local school district canceled classes for the rest of the week.

Exposure to low doses of butadiene can irritate the eyes, nose, throat and lungs, according to the Occupational Safety and Health Administration. Higher doses can cause more serious issues such as vertigo, nausea, low blood pressure and fainting. Long-term exposure can cause cancer.

In its statement Wednesday night, Jefferson County said that Unified Command — a coalition of local, state and federal environmental and emergency management agencies actively responding to the incident — is "continuously monitoring air in the community and will provide an update once an all clear is given."

County leaders scheduled a press conference for 2 p.m. Thursday.

Many residents expressed frustration over the late nature of the evacuation order in Facebook posts Thursday, saying they were already asleep when it was announced.

The U.S. Environmental Protection Agency has considered the TPC facility a high-priority violator for more than two years. State data shows the facility has reported spewing more air pollution than allowed by its government-issued permits five times this year, including hundreds of pounds of butadiene.