Lead paint was legal in Canada up to 1978, so you almost certainly have to properly prep surfaces that contain concentrations of lead now considered dangerous.
Painting over lead based paint isn’t dangerous, but any kind of prep work that creates dust is. If you do have to strip lead paint chemically wear a respirator, gloves and disposable coveralls. Never heat lead paint with a torch, but infrared paint strippers are a safe way to soften paint without liberating lead vapours. Always dispose of stripped lead paint as toxic waste.