(CNN) Ten Covid-19 unit nurses are heading back to work after being placed on paid administrative leave for refusing to enter coronavirus patient rooms without an N95 mask.

Providence Saint John's Health Center in Santa Monica, California, confirmed the nurses were returning to work after they were put on paid leave April 9 , hospital officials told CNN in a statement.

But Jack Cline, one of the nurses put on leave, said that while the hospital did reinstate them, it also submitted a disciplinary action -- a written warning -- in their employee files.

Cline shared with CNN a three-page document from the health center titled, "Corrective Action." He said he has refused to sign the document, which is the written warning from the hospital for what it says is his "insubordination" and "refusal to follow a direct order" on April 9.

"They said it would stay in our file for three months and then they will take it out," Cline told CNN. "Usually a write-up stays in longer than that."

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