An 11-day flow halt following a spill on TC Energy Corp.’s Keystone oil pipeline to the United States depressed Canadian international trade into deficit territory last fall, according to Statistics Canada.

“Energy products drove the overall export decrease, down 7.4% on lower exports of crude oil,” according to the monthly trade assessment issued Tuesday.

“Export volumes were behind the crude oil decline in November, a month that was marked by disruptions in crude oil pipeline transportation following a rupture that occurred in late October,” said Statistics Canada, the government’s recordkeeping agency.

The spill on the North Dakota leg of the 590,000 b/d Keystone pipeline shut in about 16% of Canada’s 3.8 million b/d exports to the United States from Oct. 29 to Nov. 9.

Deliveries from Alberta to refineries on the Gulf of Mexico in Texas were cut off while a 200-strong emergency response crew repaired the leak and recovered about 6,540 bbl, or 72% of the 9,120 bbl spilled.

The loss on oil was only offset partially by a 31% increase in the value of Canadian natural gas exports to the United States following severely depressed prices in late summer and early fall, according to the Statistics Canada data.

TC subsidiary Nova Gas Transmission Ltd. last month said gas-related drilling and pipeline expansions in the United States had escalated rivalries across all destinations for Canada gas. 

Value gains on other export items such as metal products were also too small to eliminate Canada’s overall international merchandise trade deficit, which was C$1.1 billion ($825 million) for last November.

The cause of the Keystone spill remains under investigation by TC, the U.S. Pipeline and Hazardous Materials Safety Administration and North Dakota’s Department of Environmental Quality. 

The mishap has become ammunition in continuing protest lawsuits against the hotly contested second stage of Keystone XL, TC Energy’s 830,000 b/d oilsands export pipeline.