A C$63.3 million ($47.5 million) cleanup chore has been approved for two pipelines left empty when 19 years of natural gas production ended offshore of Nova Scotia at the end of 2018.

Canada's National Energy Board authorized the Sable Offshore Energy Project and the smaller Deep Panuke platform to purge, seal and abandon their combined 370 kilometers (222 miles) of ocean floor pipe.

A parallel cleanup of depleted wells and idled production hardware is underway under safety and environmental supervision by the Canada-Nova Scotia Offshore Petroleum Board.

Canadian east coast gas markets switched to deliveries from the United States, using imports obtained by reversing flows on the Maritimes & Northeast Pipeline (M&NP) that was completed in 1999 for Canadian exports from the offshore production networks.

M&NP flows peaked at about 536 MMcf/d, but dwindled as the high-cost operations offshore of Nova Scotia turned out to be uncompetitive with gas from the U.S. Appalachian region.

Popular provincial government bans against horizontal drilling and hydraulic fracturing prevented replacing the offshore wells with shale production in Nova Scotia and New Brunswick. A new toll regime for M&NP's changed role as a Canadian import service is under negotiation.