Canada National Railway (CN) and Canadian Pacific Kansas City (CPKC) have both started halting rail shipments of hazardous materials, in anticipation of a potential rail worker strike.

The Canadian Press reports that both CN and CPKC began to embargo shipments of toxic chemicals such as chlorine and ammonia on August 12, to avoid the risk of trains carrying those materials getting stranded on rail networks during a possible work stoppage. This was after Canada's Industrial Labor Board (CIRB) ruled on August 9 that there are no critical shipments that would be required to continued in the event of a strike. The CIRB also imposed a 13-day "cooling-off" period before any stoppage can occur. Shortly after that ruling, CN and CPKC said that they plan to lock rail workers out at the end of the cool-off period on August 22, if a new collective bargaining agreement hasn't been reached with the union. 

The Chemical Industry Association of Canada (CIAC) — a coalition of stakeholders across the country's chemical and plastics industries — estimates that more than $76 million worth of industrial chemical products are moved by rail in Canada each day, as well as $28 billion annually. In a release responding to the CIRB's ruling, the CIAC warned that there are "no viable alternatives" for transporting hazardous chemicals during a strike, and that some manufacturers would have to shut down their operations within just two days of a rail work stoppage. 

“The Canadian chemistry sector alone moves over 500 rail cars per day; it would require over 1,500 road-based tanker trucks to carry the same load," said CIAC president and CEO Bob Masterson. "There is no Plan B, due to the lack of availability of such trucks and drivers, the additional costs to move the products over long distances, and the fact that many chemistry products are restricted to movement on rail due to their hazardous nature." 

The two railways have been locked in a standoff with Teamsters National Rail Conference (TCRC) — the union representing Canada's rail workers — for months. Negotiations had been halted after the CIRB began its review of critical shipments in June, before talks resumed in Calgary on August 9. CN said that "no progress" was made during those renewed negotiations, while TCRC has told its members to "move forward and prepare" for a work stoppage by August 22.