OTTAWA – An unfortunate choice of words on the part of Transport Minister Marc Garneau at the end of question period on Monday had Green Party Leader Elizabeth May calling on her fellow MPs to show some maturity.

May rose in the House of Commons to ask Garneau about a piece in his mandate letter on the Navigable Waters Protection Act. She called on him to honour his government’s commitment and restore protections removed by the previous Conservative government, expressing concern that the Liberals were falling short.

In his answer, Garneau said: “I remember spending all night long with my honourable colleague when…”

At that point, heckling began and Garneau appeared to smirk. He continued: “…when the previous government gutted the navigation protection act.”

He was referencing the 24 hours of non-stop voting that May triggered in the last Parliament, in protest over a Conservative omnibus bill that made a number of changes to environmental laws, including removing environmental protections. At the time, May tabled 400 amendments that, with the support of the Liberals and NDP, forced a vote on each amendment. None of her changes ended up passing.

In a separate omnibus Conservative government bill, the Navigable Waters Protection Act was "gutted," as Garneau put it Monday.

It was a campaign promise of the Liberals in 2015 to review the changes made by the previous government and reestablish protections, which ended up on Garneau’s mandate letter, as well as on Fisheries, Oceans and the Canadian Coast Guard Minister Dominic LeBlanc’s mandate letter. They have been asked by Prime Minister Justin Trudeau to “review the previous government’s changes to the Fisheries and Navigable Waters Protection Acts, restore lost protections, and incorporate modern safeguards.”

When Garneau finished his answer -- in which he said the government will “go beyond” recovering what was lost in the previous act -- House of Commons Speaker Geoff Regan said he “would encourage members to be careful in their wording.”

MPs Laughter ensued, and May rose on a point of order -- a pause in proceedings where a member can question whether the procedures are being properly followed -- to thank Garneau and to ask her colleagues “for some maturity from some members in this place,” and say the round-the-clock forced voting was a “principled stand” that “should not be the source of school yard bullying.”

From the view inside the House of Commons, it appears Liberal members on the front bench were standing to applaud May’s comments, while the Conservatives across the aisle that were in camera view were sitting down.