Any interested person may file with the Board a charge that employees eligible to vote in an election under this chapter have been coerced or restrained in the exercise of this right. The Board shall investigate the charge. If, upon the basis of its findings, the Board concludes that employees eligible to vote in the election were so coerced or restrained, the Board may set aside such election and order another election and may begin proceedings under section 1622 of this title. No election shall be set aside unless the Board finds such coercion or restraint. (Added 1967, No. 198, § 13.)