The federal government has done a poor job of educating people about travelling with cannabis-related products, an immigration lawyer says, after two recent cases where Canadians were denied crossing a border because they were carrying cannabidiol (CBD) oil.

Less than two weeks ago, a Canadian woman was barred from crossing the U.S. border in Washington state after a bottle of CBD oil was found in her backpack.

Earlier this month, Brett Heuchert, a Canadian man travelling to the U.S. from Tokyo, was detained for several hours at Seattle's airport after customs officials found two bottles of CBD oil he was carrying.

Len Saunders, the immigration lawyer representing both Canadians, says the two cases are "just the tip of the iceberg."

"Everyone knows you can't bring cannabis to the U.S.," said Saunders. "What the Canadian government hasn't done is advise people of all of these derivatives, the oils, any of the edibles. They haven't told Canadians that those are considered the same as bringing leafy marijuana."

On its website, the Canada Border Services Agency states that "transporting cannabis across the border in any form — including any oils containing THC or cannabidiol (CBD) — without a permit or exemption authorized by Health Canada remains a serious criminal offence," even after legalization.

Heuchert says he uses CBD oil, a non-psychoactive product of the cannabis plant, to treat his anxiety and sleep troubles.

"I thought nothing of it," said Heuchert of crossing borders with the oil. "To me CBD is very harmless so I flew to Washington and they randomly selected me for a search."

In August 2019, Brett Heuchert was detained for several hours at Seattle's airport after customs officials found two bottles of CBD oil he was carrying. (Mike Segar/Reuters)

Trace amounts of THC, the psychoactive element of cannabis, were detected on one of the bottles he had purchased in Japan. He says the label on the bottle said they contained no THC and he believed he could travel with them as CBD products are legal in Japan and in Washington state.

But cannabis and its derivatives are deemed a controlled substance under U.S. federal law and possessing them is a criminal offence — and ports of entry, like airports, are governed by federal law.

After being denied entry and questioned at the Seattle airport, Heuchert was deported to Vancouver. He now faces a $500 customs fine and will have to apply for a special waiver to be allowed back into the U.S.

Saunders believes there will be more cases like Heuchert's as edibles and other cannabis derivatives become legal in Canada this October.

"This is what's going to happen in the future at the border until the U.S. federal government legalizes cannabis," said Saunders, who works out of Blaine, Wash. "You're going to see this uncertainty."

He warns travellers to make sure to leave any cannabis products behind before crossing the border and recommends sanitizing bags, clothes and cars the products may have come in contact with.