How weather is affecting air quality after Crosby plant fire

HOUSTON – The weather played an important role Tuesday during the KMCO plant fire in Crosby.

While the fire burned, calm wind and high pressure served as a significant benefit to surrounding areas.

The lack of wind allowed the heat from the fire to lift smoke and toxins vertically very quickly.  The smoke plume extended well above ground level, keeping essentially all of the toxins well away from people. The local National Weather Service office estimates that the smoke lifted to between 2,500 and 4,500 feet above the ground before being fanned laterally by a stronger upper-level wind.

High pressure centered over the Houston metropolitan area served as a benefit, too. High pressure creates a stable atmosphere, preventing vertical mixing of the air in the atmosphere. The lack of mixing prevents the smoke high above the surface from drifting back down to ground level and affecting people.

After a fire, a calm wind can have a much different effect on chemical releases from a plant than a strong wind. If gases escape from the damaged equipment after the fire is out, there is no heat to help propel the fumes or toxins upward and away from people on the ground. Depending on their properties, these gases could instead pool near the ground. In this case, a stronger surface wind could help to dilute and disperse chemicals and keep concentrations below hazardous limits.

To view the latest air quality readings from the Texas Commission on Environmental Quality, go to TCEQ.texas.gov or AirNow.gov.