Mont. Code Ann. § 39-71-412

The right to compensation and medical benefits as provided by this chapter is not affected by the fact that the injury, occupational disease, or death is caused by the negligence of a third party other than the employer or the servants or employees of the employer. Whenever injury, occupational disease, or death occurs to an employee while performing the duties of employment and the event is caused by the act or omission of some persons or corporations other than the employee's employer or the servants or employees of the employee's employer, the employee or in case of death the employee's heirs or personal representative, in addition to the right to receive compensation under this chapter, has a right to prosecute any cause of action that the employee or heirs may have for damages against the persons or corporations.