OKLAHOMA CITY - A rough day for Oklahoma's oil and gas sector Tuesday, as Oklahoma City-based Chesapeake Energy announced another major layoff - 13 percent of its workforce. That about 400 workers.

Tuesday morning, employees were handed pink slips as part of an ongoing effort to reduce debt and maximize efficiency.

Under co-founder Aubrey McClendon, Chesapeake had grown into the 2nd-largest producer of natural gas, with a sprawling northwest Oklahoma City campus and more than 10-thousand employees company-wide.

But concerns about McClendon's risk-taking, accumulation of debt, and very serious governance issues, led to his ouster early in 2013.

The Doug Lawler era at Chesapeake began in June 2013.

In October 2013, as part of an initial reorganization, about 900 workers were let go, and there would be more to come.

Two years later, in September 2015, with commodity prices tanking, and the company still trying to slough off debt, Lawler made the call to let another 750 employees go.

In a letter to employees Tuesday, Lawler said the company's divested 25 percent of its wells in the last couple of years.

The result is, as those deals have finalized, they don't need as much administrative staff, which helps explain the layoff of 400, and 330 of those were in Oklahoma City.

Also in his letter, Lawler said transforming a company requires discipline and tough decisions. No doubt, this was one of them.