Canadians who work in the marijuana industry — and those who invest in the booming pot sector — will face significant risks when crossing the U.S. border even after the drug becomes legal in Canada next month, according to detailed comments by a senior official overseeing U.S border operations.

A lifetime ban on entering the U.S. will apply to travellers who admit to using marijuana, employees in the marijuana industry, and investors in the marijuana sector, according to the official.

“We don’t recognize that as a legal business,” Todd Owen, executive assistant commissioner for the Office of Field Operations at CBP, told POLITICO Pro Canada, a new subscription news service and daily newsletter focused on Canada-U.S. relations.

Owen said U.S. Customs and Border Protection will apply existing laws against admitting drug users and drug traffickers into the United States. Among the details he laid out: