Mont. Code Ann. § 39-32-110

It shall be unlawful for any employee of a health care facility, as defined in 39-32-102, to participate in a strike if there is another strike in effect at another health care facility within a radius of 150 miles. Employees of a health care facility, as defined in 39-32-102, or their duly elected representative must give the health care facility 30 days' written notice of any strike by them and must specify in the notice the day the strike is to begin.