TULSA, Okla. (AP) — Declining crude oil prices have forced three major industry firms  to lay off workers.

Apache Corp., Baker Hughes and Schlumberger have begun laying off employees in response to the oil price crash in the past six months.

Two weeks ago, Denver-based producer SM Energy announced it would close its Tulsa office, which employs 100 people.

Apache Corp. has announced across-the-board job cuts that will likely impact several hundred employees companywide and at least some in Tulsa. The Houston-based oil and gas producer is one of the nation's bigger independent firms.

Houston-based oilfield service firm Schlumberger is letting go of 9,000 employees and would not say whether the layoffs will directly affect workers at its Bartlesville plant.

And today, Baker-Hughes announced it will cut its workforce by 7000 jobs.

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