(Reuters) -U.S. President Donald Trump signed a proclamation on Friday to ease regulatory requirements on certain coke oven processing plants, the White House said.

Coke ovens are manufacturing plants or blast furnaces for making coking coal, a key raw material in steelmaking.

The proclamation gives some plants an exemption from certain emissions requirements for a period of 2 years beyond their compliance dates under the Coke Oven Rule, according to the text of the proclamation released by the White House.