Transport Canada estimates as much as $3.9 billion in trade activity was halted because of border blockades across the country related to protests against COVID-19 restrictions last winter.

The Public Order Emergency Commission reviewed emails between staff for various federal ministers who were hearing from businesses frustrated with border blockades between Feb. 8 and 9.

The commission is holding public hearings to investigate the events that led to the federal government鈥檚 decision to invoke the Emergencies Act for the first time since it replaced the War Measures Act in 1988.

Prime Minister Justin Trudeau referred to the economic impact of the blockades and the undermining of Canada鈥檚 economic and national security in the emergency declaration Feb. 14.

The emails show that in the lead-up to the decision, motor companies expressed concerns to Transport Minister Omar Alghabra鈥檚 office about having to shut down their manufacturing plants.

When Ford Canada shut down production at an Oakville plant during the Windsor border blockade, Alghabra鈥檚 chief of staff noted the situation was being seen by U.S. parent companies as 鈥渏ust another reason not to invest in Canada.鈥�