Frigid weather this month caused industrial facilities across Texas to release unplanned air pollution as machinery froze, power went out and icy conditions blocked service crews.

Over four chilly days between Jan. 14 and 17, companies submitted reports to Texas’ environmental regulator, the Texas Commission on Environmental Quality, that attributed at least 36 instances of “unintentional” emissions to the freezing temperatures.

Read more from Alejandra Martinez, The Texas Tribune, and Dylan Baddour, Inside Climate News, from The Texas Tribune here.