Less than two weeks after a Canadian woman was barred from entering the United States after she was found with cannabidiol (CBD) oil at the border, her lifetime ban from entering the states has been reversed in what her lawyer is calling a "best-case scenario."

The 21-year-old, who has asked not to be identified by CBC News, was crossing the border between B.C. and Washington state last month when CBD oil was found in her backpack.

CBD is a non-psychoactive product of the cannabis plant. The woman said she uses it to treat the painful side-effects of scoliosis.

She said she thought it was OK for the oil to be carried over the border, considering such products are legal in both British Columbia and Washington. But while some states have dismantled prohibition, cannabis possession remains a criminal offence federally, and the U.S. border is governed by federal law.

The woman, an undergraduate student at the University of Guelph in Ontario, was fined $500 for failing to declare the oil, fingerprinted and subsequently denied entry to the U.S.

She was told if she ever hoped to regain entry to the U.S., she would have to pay an additional $585 to apply for a special waiver, a document required for all people denied admission after deportation or removal.

'180-degree turn'

Lawyer Len Saunders, who had been working with the woman to fill out that application, said his client was unexpectedly contacted by a supervisor at the Point Roberts, Wash., point of entry on Friday and told her inadmissibility case had been reversed and she would no longer be required to apply for the waiver.

"My reaction obviously was shock. I was shocked that it was such a 180-degree turn from basically being barred for life to being told that they had on their own reviewed the case and had basically reversed their decision," said Saunders, who is based in the border city of Blaine, Wash.

The port of entry did not provide the woman, or Saunders, a reason for the reversal, he said.

In a statement sent to CBC News on Wednesday, U.S. Customs and Border Protection confirmed the lifetime ban had been reversed, but a spokesperson declined to elaborate on the reasons for the agency's decision.

A spokesperson said the case was automatically reviewed, as are all cases in which travellers are deemed inadmissible.

"In this particular case, management determined that [the woman] did not meet the terms for inadmissibility.... Determinations about admissibility are made on a case-by-case basis by a CBP officer based on the facts and circumstances known to the officer at the time," the spokesperson wrote in an email.

"In some instances, decisions about admissibility may be changed upon further review and presentation of additional information, verification of further evidence, etc."

Depending on the product, CBD oil usually contains only trace amounts of tetrahydrocannabinol (THC) — the principal psychoactive compound in cannabis — and typically does not produce any sort of high. (Mike Segar/Reuters)

Saunders said the case highlights the confusion around cannabis laws and international borders.

"Did they decide themselves that having CBD oil is not the same as having THC or cannabis? At this point I don't know," the lawyer said.

Depending on the product, CBD oil usually contains only trace amounts of tetrahydrocannabinol (THC) — the principal psychoactive compound in cannabis — and typically does not produce any sort of high.

'A moving target'

On its website, the Canada Border Services Agency said "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.

But Saunders said the federal government has done a poor job of educating people about travelling with cannabis-related products, and regulations remain "a moving target."

"Going forward all I can tell people is to be cautious on what they bring to the United States because who knows, today CBD oil is OK, but CBD oil next month may not be. Nobody really knows what's going on," he said.

Saunders said his client, who has since returned to Ontario, is immensely relieved by the outcome.

Saunders is working on a similar case involving a Canadian man who was travelling to the U.S. from Tokyo, and was detained for several hours at Seattle's airport after customs officials found he was carrying two bottles of CBD oil.

He said he now plans to reach out to U.S. Customs and Border Protection at Seattle's Sea-Tac Airport to see if it will also reverse its decision to issue a lifetime ban.

"It should be consistent [no matter] the border — there needs to be consistent application of the law," Saunders said.