Energy companies are at greater risk of defaulting on their bonds as oil prices show little sign of recovering from 13-year lows. Companies may resort to cutting more jobs to stay afloat.

Nearly half of investment-grade bonds of oil-and-gas companies are trading at junk levels as of this month, according to data from asset-management company Invesco Ltd. that are cited by The Wall Street Journal.

Drillers binged on debt as the Federal Reserve cut interest rates to nearly zero percent in an attempt to revive the economy from the worst recession in 80 years. Now, about $199 billion of those bonds are highly speculative.

Companies with investment-grade debt currently trading at junk levels include Hess Corp., Devon Energy Corp. and Williams Partners LP, according to data from MarketAxess cited by the WSJ.

Credit downgrades will make it harder for companies to refinance existing debt or to fund new drilling projects. Already, the energy industry has shed 250,000 jobs worldwide with the 70 percent collapse of oil prices since mid-2014.

Texan exploration and production companies have shed at least 60,000 jobs, Karr Ingham, petroleum economist for Texas Alliance of Energy Producers, told USAToday last month. That’s about one-fifth of their workforce in the state.

“I expect it to get worse in the near term,” Ingham said. “Expenses have to be cut pretty dramatically and that means that employees on payrolls have to go."

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