Me. Rev. Stat. tit. 39-A, § 613

In the absence of evidence in favor of the claim, disability or death from silicosis is presumed not to be due to the nature of any occupation, unless during the 15 years immediately preceding the date of disability the employee was exposed to the inhalation of silica dust over a period of at least 2 years. If the employee has been employed by the same employer during the whole of the 2-year period, the employee's right to compensation against such employer is affected by the fact that the employee had been employed during any part of the 2-year period outside of the State.