(a) Except as provided in paragraph (c) of this section, barges certified for, or used within the previous 2 years prior to the effective date of this regulation, or barges equivalent to such barges, for the transportation of any cargo regulated by this subchapter which do not meet the specific requirements herein, may be continued in service subject to the following conditions:
(1) Venting, gauging, and all operating requirements shall be met within a 1-year period subsequent to the effective date.
(2) All other requirements shall be met within a 2-year period subsequent to the effective date.
(b) If an existing barge, which has been designed to carry or has regularly been carrying one or more of the cargoes regulated by this subchapter, is found to be so arranged, or outfitted that conversion to bring it into compliance with any or all of the requirements of this subchapter is impractical or impossible, the Commandant, upon application, may review the plans of the barge to determine if it is suitable and safe for the cargoes to be transported.
(c) Except for operating and vinyl chloride requirements, barges constructed and certificated for the transportation of any cargo for which specific regulations existed, in parts 36, 38, 39, 40, and 98 of this chapter at the time of their construction or conversion, may continue and will be certificated to operate without the requirement that they comply with the provisions of subchapter O of this chapter.