BANGOR — Eastern Maine Medical Center nurses have given notice that they intend to hold a second one-day strike as they continue working without a contract.

The Bangor Daily News says the nurses’ union has issued a 10-day notice calling for a strike on May 5 over what it says is the hospital’s refusal to address patient safety concerns related to nurse staffing levels. About 830 EMMC nurses have been working without a contract since September and held a one-day strike in November.

Hospital officials maintain that staffing levels are safe and meet national standards. They say the hospital is prepared for a strike and would bring in replacement nurses for the day.