Those workplaces include banks, federal government buildings, airlines, ports and First Nations reserves.
Bruce McKeigan, a health and safety inspector for Labour Canada who has worked in the industry for decades, said he's concerned about the staff reductions. He investigated the death of Peter Kennedy, who died in a boiler explosion in 2009.
In northern Ontario alone, he said, there is one inspector to cover the whole area.
"It's very frustrating on a number of levels," he said.
Proactive investigations happening less and less: union
The union representing the inspectors says the loss of workers, whether through attrition or lack of training, means proactive safety investigations are happening in those workplaces less and less.
"They don't have enough people … the resources to do the inspections," said Doug Marshall, who heads the union that oversees inspectors. "So all they can do is respond. So when there's a workplace accident, when there's a refusal to perform unsafe work, that's what they respond to."
About 80 per cent of the work inspectors do is supposed to proactively prevent workplace injuries and more, Marshall said, but that's not happening as often because of a lack of resources.
Employers know that, Marshall said, and can judge their risk accordingly.
"Employers know that their likelihood of … an inspection taking place is less and less. So they look at their risk and they make decisions," he said.
Proactive work still a priority despite job losses: government
Canada's research chair in occupational health and safety law at the University of Ottawa said it's a "very, very serious concern" for her.
"What we can see is that there is, both federally and provincially, lots of pressure to do more with less," Katherine Lippel said. "It depends on the provinces, but certainly federally its very, very clear that there are fewer inspectors than there used to be and that's true in other provinces as well.
"From what I've been seeing … it's a very serious concern in the sense that not only can they not do proactive inspections, but what I've been reading … is that they can't even get to the accidents very quickly because they don't cover the territory."
Human Resources and Skills Development Canada said that while there have been job losses, proactive work is still a priority.
The number of disabling injuries in federal jurisdiction has also gone down, the department said.