Three Conservative senators were in Washington D.C. this week for meetings with U.S. Attorney General Jeff Sessions and other federal officials to discuss Canada's plan to legalize recreational cannabis use — and they say officials there have unanswered questions of their own about the pot bill.

Senators Claude Carignan, Pierre-Hugues Boisvenu and Denise Batters said they went to Washington after getting what they called unsatisfactory answers from Public Safety Minister Ralph Goodale last week at a Senate committee about the the impact legalization will have on the Canada-U.S. relationship.

"We went to Washington to find clear answers to the questions asked by Canadian workers and tourists, including families, who cross the border," Sen. Boisvenu said in a statement. "Faced with the Liberals' empty answers and broken record, we had to seek concrete and real facts right at the source."

The three senators, who arrived in Washington Tuesday, are all outspoken critics of Prime Minister Justin Trudeau's plan to legalize the recreational consumption of cannabis in Canada.

They said they went to the U.S. to ask about the policy's impacts on border security and cross-border trade. They also had questions about issues linked to trucking and "public transportation safety," and the risks faced by Canadians travelling into the U.S. with small quantities of cannabis.

In a joint statement after the meeting with Sessions, the senators said they were told that anyone who admits to having consumed marijuana may be subjected to additional inspection or even denied entry to the U.S.

"Canadians have reasons to be worried!" the senators said in the statement. "An increase in standby time is expected for crossing the U.S. border, for both regular and Nexus travelers as well as truckers (Passexpress). Travelers can expect an increase of secondary inspections as trained dogs will still detect residue and smell marijuana odours even if the consumption dates back a few days."

Batters told CBC News the senators wanted to speak directly to U.S. officials to be "in full understanding of what these particular bills can mean for Canadians — and there could be significant consequences for Canadians."

The senators met with Sessions — and other members of the Trump administration — for 45 minutes Wednesday.

Conservative senators have complained that the Liberal government is not giving them the information they need to properly study the marijuana legalization bill, C-45.

The senators said they wanted to know if U.S. Customs intends to change the questions its officers ask of travellers at the border — and whether a Canadian who admits to having used marijuana will still be allowed to enter the United States.

They also said they spoke with people they described as "high-level advisers" to the Trump administration, including officials at the Department of Homeland Security, the Office of Strategy, Policy and Plans, the U.S. Customs and Border Protections Office of Field Operations and other agencies.

"When we ask questions of the Canadian government, we receive unclear and vague responses which do not satisfy us. Our role as legislators is to measure all the impacts of Bill C-45, and that is what we are doing today by meeting with senior officials of the U.S. Department of Homeland Security," said Sen. Carignan.

The senators said Homeland Security officials expressed "great concerns" about marijuana smuggling.

'In Colorado, organized crime has created new cartels operating under the appearance of a legitimate industry. U.S. authorities are worried about new contraband activities developing in Canada and crossing the border. In states that have legalized marijuana, law enforcement is struggling to deal with these new cartels," the senators said in their statement.

The Tories said U.S. officials were "taken aback" when they learned there are no random testing measures in place in Canada for public transport operations (planes, trains, buses, etc.). Such measures have existed in the U.S. for more than 10 years.

Last January, the Trump administration announced that U.S. authorities could make arrests by enforcing federal law on cannabis use, even in states that have legalized marijuana.

In March, Sessions said federal officials, facing a shortfall in resources, would focus on criminal gangs and not on minor cases of possession. Several states, including Colorado, Washington State and California, allow the use of cannabis for recreational purposes.

When C-45 was last before the Senate, the Conservatives voted against it at second reading, but the legislative process continued with the support of an overwhelming majority of independent senators in the upper chamber.

A final vote is scheduled in the Upper House on June 7.