Berkshire Health Systems says passage of a November ballot question would force it to add 125 full-time-equivalent jobs for registered nurses, pushing its costs up by 4 percent, and could result in turning away patients.

The Berkshire Eagle reports backers of Question 1 call the cost estimates released this week by Berkshire Health Systems and other hospitals inflated. Members of the voting public face wildly divergent predictions on the referendum's impact on health care in Massachusetts.

The ballot question would cap the number of patients who can be assigned to one nurse. State legislation already sets limits for intensive care units, but not for other hospital units.

The issue reprises, on a statewide scale, a battle that played out at BMC over two years, as members of the Massachusetts Nurses Association worked to build similar language on staffing into a new contract.

The two sides reached an accord in June, after a one-day strike and four-day lockout last October and amid threats of another job action this year. The new pact runs through September 2021.

While members of the MNA did not secure provisions related to minimum staffing levels for RNs in Pittsfield, the agreement includes language stipulating that workloads for RNs will not grow worse.

Now, the hospital is turning to what it sees as its next fiscal crisis: mandated staffing levels.

Berkshire Health has calculated that if the measure is approved by voters Nov. 6, it would push costs for Berkshire Medical Center up by $23 million a year. The increase at the smaller Fairview Hospital in Great Barrington, which it runs, would be $1.4 million.

But a study produced on the other side of the issue pegs the cost far below that, at $35 million to $46.8 million. As with the hospital study, the research isn't fully independent. It was produced by a Boston College researcher who is a former president of the Massachusetts Nurses Association.

In a statement, the hospital's leaders cautioned that passage of Question 1 could lead it to decline patient admissions to avoid violating staffing ratios.