A new state law to curb forced overtime for nurses and other direct patient care hourly workers has spawned both differing interpretations of when exceptions apply and worries that hospitals may work short-staffed.

Just one month after the law went into effect, many say it is too soon to know exactly how it will play out. But already, one thing is clear: Parties looking at the same law sometimes see different meanings.

The Prohibition of Excessive Overtime in Health Care Act, which took effect July 1, states that a health care facility may not require staff members to work overtime except under certain, specific circumstances such as a natural disaster, a widespread disease outbreak or an act of terrorism.

Another exception is for "unexpected absences, discovered at or before the commencement of a scheduled shift, which could not be prudently planned for by an employer, and which would significantly affect patient safety."

Neal Bisno, president of SEIU Health Care Pennsylvania, said this applies to only truly exceptional circumstances, such as a group of nurses carpooling to work and getting into a traffic accident. One nurse calling off at the last minute does not qualify, he said.

"The exception is for unexpected absences -- in the plural -- that can't be prudently planned for and that would significantly affect patient safety," he said. "Even in those rare instances, health-care employers are required to use forced overtime as a last resort and to exhaust reasonable efforts to avoid it."

But Paula Bussard, senior vice president at the Hospital and Healthsystem Association of Pennsylvania, says the exception can apply if one nurse calls off.

"If a nurse calls off shortly before the start of shift, that's an unexpected absence. What if it's a nurse with highly specialized skills?" she asked.

The better standard, she said, is simply to require safe staffing based on patient acuity and nurse competency. That would allow enough flexibility for the staff to respond to "the complexity of patient conditions and the changing nature of care," she said.

Spokesmen for the agency responsible for enforcing the mandatory overtime law, Pennsylvania's Department of Labor and Industry, said mandatory overtime "should be utilized as a last resort" and that requiring overtime due to chronic short-staffing is not allowed.

"There is no specific time period for the call-in to occur. Each situation will have to be reviewed independently," said Troy Thompson, press secretary for the department.

"Hospitals are supposed to have some mechanism in place" for finding a last-minute replacement, such as a list of people who volunteer to work extra, or access to per diem staff or a temp agency, he added.

"They have to exhaust those reasonable efforts before they go into mandatory overtime."

Vicki DiLeo, executive director of the state House Labor Relations Committee, where the mandatory overtime bill originated, said: "The exception was not intended to be something that was for everyday use. They didn't want to have employers using that as a reason to enforce mandatory overtime."

Ms. Bussard pointed out that in a statewide survey of hospital nurses released last year, 10.1 percent reported they'd been required to work overtime in the previous two weeks. She believes that percentage is decreasing. Although the law took effect last month, she said, "the bill passed months ago, so hospitals really have been working for a much longer time period to make sure they're compliant."

Lois Cusick, a nurse at Western Psychiatric Institute and Clinic and president of the Service Employees International Union local representing WPIC nurses, said most of the law's listed exceptions were unnecessary.

"Nurses do not have to be 'mandated' during state and national emergencies to continue working. In all my 30 years of inpatient nursing I have never witnessed a nurse leave the hospital during an emergency situation," she said.

"If I was ever scheduled to work and there was a potentially dangerous weather forecast for that day, I automatically packed an overnight bag and prepared to be away from home for as long as it took for the next shift of nurses to arrive."

But she is concerned that full staffing could be the first victim of the mandatory overtime law.

She said that since the law was passed, she was not aware of any WPIC nurses being required to work overtime. But two weeks ago, she said, two Western Psychiatric Institute and Clinic nurses who work on the separate adult "dual diagnosis" units -- units that treat patients who have both mental health ailments and alcohol or drug addictions -- called off sick the same day.

One nurse scheduled for the smaller 5 East unit offered to fill the vacancy on the 10th floor, but that left one nurse on the 13-bed 5 East for 12 hours, she said. There were other staff members, such as aides, present.

Although additional support is in the building, "it's a problem because you don't want to have medical issues reach a crisis situation," said Ms. Cusick, who also works on the 10th-floor unit.

WPIC spokeswoman Megan Grote Quatrini denied that any nurses called off that day, and in response to follow-up queries stated that "adequate staffing was in place on these and all other units at WPIC."

Although Pennsylvania currently does not have minimum staffing requirements, the House Health and Human Services Committee is currently considering a bill that would set specific nurse-to-patient ratios in different hospital settings.

Without such a requirement, Ms. Cusick worries that "adequate staffing" could become a downward sliding standard.

When she was working on the 10th floor on the weekend of July 25 and 26, two nurses were off due to injuries and "several new nurses are not yet off orientation," she said.

"From 7:30 to 11:30 p.m., it was just me and a manager working on the 10th floor with 38 patients. Nothing bad happened, but the potential is always there."

The added work and stress also takes its toll, she said, adding that turnover at WPIC has ranged from 10 percent to 17 percent in recent years.

"If nurses feel overwhelmed with the position, they will leave."