Certified tradespeople from across Ontario gathered at Queen's Park on Wednesday to protest against a provincial bill they say has the potential to threaten their jobs and put their safety on the line.

"Everybody here is mad as hell that this is being rammed through," said organizer John Grimshaw, who estimated that 4,500 people were gathered at the peak of the demonstration.

The concern is around one section of Bill 70, Ontario's budget implementation legislation. That section, known as schedule 17, would give the Ontario Labour Relations Board (OLRB) the power to review or overrule some decisions made by the industry-run Ontario College of Trades.

Tradespeople worry that the OLRB will give a free pass to non-certified workers who are caught doing jobs normally reserved for certified tradespeople.

'We've been trying to let the government know how important it is to maintain the integrity of the trades,' said John Grimshaw. who organized the protest. (Martin Trainor/CBC)

Grimshaw, who is the executive secretary-treasurer of the International Brotherhood of Electrical Workers Construction Council of Ontario, said that schedule 17 would "erode public safety, worker safety, and consumer protection."

"Our lawyers tell us it's very likely that it is going to erode our scopes of practice and allow untrained, unskilled workers to do the work because it's cheaper," he said.

Apprentice electrician Sam Lapierre boarded a bus at 3 a.m. to get to the protest from his home in Ottawa.

"It will make my apprenticeship useless because anyone will be able to do my trade," he said, adding that he's concerned about his future and his family if the bill passes as is.

Sam Lapierre said he is worried that the five years he'll spend learning to be an electrician won't be worth it. (Martin Trainor/CBC)

Jane Kang, another apprentice electrician, said safety is her main reason for protesting.

"If there's an unskilled worker, you never know if he knows his stuff," she said. "We want it to be safe."