Canadians involved in the legal cannabis industry are facing deep potholes on the road to entering the United States — and immigration lawyers say the federal government needs to help them navigate a way through.

The U.S. Customs and Border Protection agency sent tremors through the country’s burgeoning cannabis sector last week with word that legalization in Canada won’t change the fact that American laws treat marijuana as a banned substance, and industry insiders as drug traffickers.

Despite the fact that some jurisdictions in North America permit the use of medical and recreational marijuana, U.S. federal law continues to prohibit its sale, possession, production and distribution, an agency spokesperson said in a statement.

“Consequently, crossing the border or arriving at a U.S. port of entry in violation of this law may result in denied admission, seizure, fines, and apprehension,” the statement said.

“Working in or facilitating the proliferation of the legal marijuana industry in U.S. states where it is deemed legal or Canada may affect a foreign national’s admissibility to the United States.”

Having fast-track, frequent-traveller status such as a Nexus card is no guarantee either, warned Jon Jurmain, an immigration lawyer based in Thorold, Ont., outside St. Catharines.

“I have a U.S. citizen client who had his Nexus pulled because a dog smelled pot on his passenger, and my client answered a question about smoking pot and admitted to previously smoking pot,” Jurmain said in an email.

“No pot was found.”

The revelations are based on existing laws and policies and do not represent any change in how American border officials approach the issue of cannabis. They were first reported last week by Politico Pro Canada, a division of the U.S. website Politico.

Border Security Minister Bill Blair said Tuesday he doesn’t believe anything is going to change at the border after Oct. 17, the date the federal government has set for legalization to take effect.

“My expectation is that border security agents on both sides of the border will continue to do their job to protect the sovereignty and security of their country in the way in which they have been doing it in the past, and my expectation is that it will continue.”

Lawyers with expertise in helping people cross the Canada-U.S. border say it should fall to Ottawa — not travellers who are taking part in a perfectly legal business enterprise — to help pave the way.

Henry Chang, a Toronto-based immigration lawyer with Blaney McMurtry who specializes in Canada-U.S. matters, says the two countries have consulted productively on immigration issues in the past during the presidency of Donald Trump, and this time should be no different.

“The best chance these individuals have is for the Canadian government to pressure the U.S. government to issue a policy directive saying that employees and investors in Canadian cannabis companies are not subject to the controlled substance trafficking bar,” Chang said.

The U.S. Customs and Border Patrol agency insists it has no plans to ask any pot-specific questions without cause. But Ottawa immigration lawyer Warren Creates said he fears some agents might find it a useful catch-all to deny admittance to anyone they decide shouldn’t be allowed in.

“If a U.S. border officer has some reason not to like the person in front of them who is being examined for entry — some reason — then that officer is more likely to ask the question, ‘Have you ever been a user of cannabis or been involved in the cannabis industry?’

Creates said he doesn’t expect the question to be asked more frequently, “but I think an officer faced with an unlikeable person who has not yet presented grounds for inadmissibility . . . would be more inclined to use that tool.”

Ultimately, only Canada’s federal government has the credibility and the negotiating heft to convince the U.S. to establish clear guidelines, Chang suggested.

“If Canada is going to legalize marijuana companies, it needs to ensure that employees of and investors in those companies are not given lifetime bans as controlled substance traffickers,” he said.

Allan Rewak, executive director of the Cannabis Council of Canada, agreed Ottawa should be pressing the U.S. to reconsider what he called a “very unfortunate” and unnecessary hard line on legal marijuana users and industry members.

“As long as Canadians are not doing anything to violate U.S. laws, cannabis will be a perfectly legal and viable business in Canada and should be seen as any other business,” Rewak said.

“We’d like Canada to emphasize to our American partners that there really is no reason for this prohibition.”

In the meantime, common sense should prevail for anyone trying to enter the U.S., said Jurmain.

“I see the dogs on both sides of the border out sniffing cars,” he said.

“Do not smell like pot. Do not have people in your car who smell like pot. (And) obviously, don’t have pot.”