BANGOR – Nurses who were on the verge of striking at Eastern Maine Medical Center are at work after their union ratified an agreement on a new three-year contract.

The deal averted a threatened two-day strike by the nurses that was planned to start Monday. Negotiators announced the deal on Wednesday and the union ratified it on Friday.

A spokeswoman for Maine State Nurses Association/National Nurses Organizing Committee/National Nurses United said the key piece of the contract is the hospital’s pledge to hire 30 more registered nurses. The union had complained of a staffing shortage.

Deborah Carey Johnson, EMMC’s president and chief executive, said last week that the agreement represented a compromise. The hospital argued during negotiations that it was not understaffed.