After the fire at a petrochemical facility in southeastern Texas, the United States, was extinguished Wednesday, environmental teams Thursday morning detected increased levels of benzene around the affected area.

Firefighters battle a petrochemical fire at the Intercontinental Terminals Company Monday, March 18, 2019, in Deer Park, Texas. [File photo: AP/David J. Phillip]

The City of Deer Park issued a shelter-in-place Thursday morning due to increased levels of benzene caused by the massive fire at a petrochemical storage facility located in Deer Park, but it later lifted the shelter-in-place because of a "sustained period of improved readings."

The fire erupted on Sunday at the Intercontinental Terminals Company (ITC) Deer Park, about 40 km southeast of downtown Houston.

The fire was extinguished on Wednesday morning, but a flare occurred on Wednesday afternoon. It was put out by firefighting crews.

Local officials said the National Guard and hazardous materials teams have established perimeters around the ITC facility and are analyzing air quality readings.

Multiple school districts have canceled classes Thursday and Houston Independent School District schools located in the Deer Park area are holding all activities indoors.

According to ITC, the first tank that caught fire contains naphtha, which may cause irritation to eyes and the respiratory system. The fire then spread to a second tank containing xylene, which may cause skin irritation. Both naphtha and xylene are gasoline components.

Another tank that caught fire early Monday morning contains Toluene, which is used in nail polish remover, glue and paint thinner.

The ITC Deer Park terminal has 13.1 million barrels of capacity, which it uses to store all kinds of petrochemical liquids and gases, as well as fuel oil, bunker oil and distillates.