OTTAWA -- If Stephen Harper muzzled federal government scientists, then Justin Trudeau has failed to lift the muzzle, a federal public sector union says in a memo obtained by Postmedia Network.

Mind you, data quietly tabled in the House of Commons earlier this summer suggests that Harper's "muzzle" appeared to be ineffective. That data shows that federal government scientists gave nearly 1,500 media interviews in the 12 months prior to last October's election.

Nonetheless, the Professional Institute of the Public Service of Canada (PIPSC) -- the union that represents tens of thousands of federal government scientists -- says the Trudeau government is continuing a Harper government communications policy that prevents scientists from participating in conferences.

Moreover, "a communications policy was issued by (the Trudeau government) with the intention to end 'muzzling' but its implementation remains uneven across science-based departments," PIPSC says in a submission to Finance Minister Bill Morneau.

The union is calling on Morneau to hire another 1,500 federal government scientists and to open collective agreements to include a clause to "enshrine the principles of scientific integrity."

The government already employs about 39,000 scientists and technicians.

During the Harper years, some scientists complained they were forbidden from discussing their research, could not attend academic conferences, and that some had to wait weeks -- months, even -- for approval to speak publicly about their work.

One Environment Canada scientist wrote an anti-Harper song in 2015 (and got suspended). Others marched in a demonstration organized by PIPSC. Calgary journalist Chris Turner, who ran as a Green Party candidate in a 2012 byelection, wrote it all up in a 2013 book The War on Science: Muzzled Scientists and Wilful Blindness in Stephen Harper's Canada.

And yet, the Liberal ministers in charge of nine major federal departments that employ scientists told Parliament in writing earlier this year that when they took over from the Tories they did not change a thing when it came to communication policies for scientists.

"No internal memos, directives or emails were sent to federal scientists since (the Liberals took office) concerning the communication of scientific research and the approval process for speaking to the media," Health Minister Jane Philpott told Parliament in writing.

Environment Minister Catherine McKenna wrote that "while media requests (to speak to scientists) on policy, enforcement and international affairs require departmental approvals, this is not the case for science requests."

McKenna said that policy had been in place at least since 2008, long before the Liberals took over.

The Sun has also learned that McKenna is on track this year to make the biggest-ever year-over-year cut in the number of scientists her department employs. She'll finish this fiscal year as the boss of 3,386 scientists, a far cry from the all-time high of 3,830 scientists employed at Environment Canada just two years ago under the Harper regime.

Ministers and parliamentary secretaries from other departments that employ scientists made similar statements in writing.