Texas freeze led to massive release of air pollutants

HOUSTON: Refiners and petrochemical plants along the US Gulf Coast scrambled to shut production as an Arctic air mass spread into a region unused to frigid temperatures. The extreme cold, which killed at least two dozen people in Texas and knocked out power to more than 4 million at its peak, also hit natural gas and electric generation, cutting supplies needed to run the plants. Shutdowns led to the refineries flaring, or burning and releasing gases, to prevent damage to their processing units. That flaring darkened the skies in eastern Texas with smoke visible for miles.