International Union of Elevator Constructors (IUEC) Locals 96, 90 and 50 began striking on Wednesday.
Roughly 1,400 are off the job and 800 of them work across the Greater Toronto Area.
The halt in service means broken elevators won't get fixed and regular maintenance will be put on hold.
It's a scary thought for Michaila Plumber, who says the elevator in her Scarborough apartment has regular problems.
"(It breaks down) a couple times a day, and just not move, or sitting here on the first floor, and it won't open or nothing," Plumber said. "It's scary, pretty scary. I just hope I don't get stuck again."
Union president Ben McIntyre says his membersreceive hundreds of calls every day for elevators that are broken down, sometimes with people trapped inside.
"It could be a safety concern at any time," McIntyre said.
McIntyre says Ontario has some of the highest elevator safety standards in the country. With workers on strike, he says those standards are not being enforced.
"Certain checks have to be done on these elevating devices, at certain periods of time, but they're not getting that done today," McIntyre said.
In case of emergencies, firefighters are able to step in and assist.
The union services roughly 50,000 elevators across the GTA.