Carbo’s biggest sand client notified the company after the end of the third quarter that it would discontinue purchases, according to the statement. The company also is bracing for a weakening in the frack-sand market overall going into 2020. Shale gas driller Chesapeake Energy Corp. last week warned it may go under as a result of low energy prices.

“There is an elevated risk associated with the company meeting its existing financial forecast and the company may ultimately conclude it is unable to continue as a going concern in a future period,” the company said in the statement.

The oil-industry’s biggest hired hands have been warning that demand for crews and equipment used to frack oil and natural gas wells will continue to drop. Carbo has lost more than $3 billion in market value since the worst crude crash in a generation began five years ago.

Carbo was down 45% to 85 cents at 10:35 a.m. in New York trading.