Chesapeake Energy Corp. on Tuesday laid off about 800 employees nationwide, including about 640 in Oklahoma City, ending months of uncertainty at the Oklahoma City natural gas and oil company.

“It has been a very difficult day. This has affected a significant number of Chesapeake employees,” Chesapeake CEO Doug Lawler told The Oklahoman Tuesday. “It's been very difficult for us and for all those involved. It also is an essential step in making Chesapeake a competitive, productive, strong and vibrant company for decades to come.”

Tuesday's announcement ends the monthslong changes that have led about 1,200 people to leave the company since the first of the year.

“The principle reason I came to Chesapeake was because of my confidence in the assets and my confidence in the people. I see great value in both,” Lawler said. “I also see great opportunity for a company that has been through a difficult transition, but has all the right resources essential to be an outstanding E&P (exploration and production) company.”