Dow Chemical upset at Texas plant prompts evacuation order

A process upset at a Dow Chemical plant near the Houston Ship Channel in La Porte, Texas, prompted a shelter-in-place and an evacuation order within a half-mile radius of the facility on July 21, according to emergency management officials.

Dow said the incident involved a tank wagon emitting hydroxyethyl acrylate, a chemical used to manufacture coatings, adhesives and other products.

The city of La Porte lifted the shelter-in-place order by midday, but kept the evacuation order in place in case a chemical reaction that occurred in the tanker truck was continuing, risking a fire or explosion, Harris County Judge Lina Hidalgo said at a news conference.

The truck had been venting, which had stopped, prompting officials to lift the shelter-in-place order.

"What is not clear is whether it stopped because the reaction has stopped or whether it's stopped because there's so much reaction, so much heat and pressure being built up within that tanker that it's clogging that vent," said Hidalgo, the county's senior official.

Officials did not know why material inside the truck became unstable, she said.

The evacuation zone included two other chemical plants that continued operating with reduced staff. Those are Kuraray's unit that produces polyvinyl alcohol, and tiremaker Goodyear's plant that makes acetone, antioxidants and skin-bleaching agent hydroquinone.