A fire at a Lubrizol plant in Leetsdale Industrial Park near Pittsburgh, Pennylvania, in the US on Nov. 17 injured one worker and prompted a hazmat response by local firefighters. The company said the fire started as employees were mixing fracking chemicals in a production tank. "We were working with an oxidizer, that had an adverse reaction," plant manager Ed Michalowski told local media, adding that an investigation is in progress.

Emergency service authorities said the initial fire within the plant spread to two adjoining buildings. They confirmed that two chemicals in use were ammonium persulfate and sodium chlorite, both of which can cause inhalation problems.

Western Pennsylvania is an important center for the US shale gas industry as the Marcellus fields, said to be producing as much as 16 cubic feet of gas per day, lies within its territory.