The Chattanooga plant in Tennessee, Festus plant in Missouri, and Maryneal plant in Texas all retained the certification, which marks them out as part of the top 25% of similar plants in terms of energy performance.

“In meeting these strict qualifications, these facilities are saving energy, saving money, and helping protect the environment by using less energy than peer facilities,” the company said in a press release.

The EPA’s ENERGY STAR programme has been running for more than two decades and aims to assist facilities improve the energy performance of their buildings and plants.