No gas company, as described in § 39-1-2(a)(20), shall allow employees to terminate, restore, or activate gas services unless those employees have gained relevant experience by working for a gas company at least two (2) years and have been properly trained in the safe termination or activation or restoration of gas services. The same criteria shall also apply to the periodic testing of meters. A certification process of gas service employees shall be established and enforced by the public utilities commission.