Me. Rev. Stat. tit. 26, § 598-A

Except as required by federal law, beginning January 1, 2020, an employer may not request a social security number from a prospective employee on an employment application or during the application process for employment except for the purposes of substance use testing under subchapter 3‑A or a preemployment background check. This section does not apply to an employer's request for a social security number after the employee has been hired.