Are we allowed to ban workers from smoking inside our plant?
Yes. You’re not only allowed but required to ban indoor smoking.
Every jurisdiction in Canada has adopted a law (called a smoke-free, tobacco-control or non-smokers’ protection act) requiring property owners to ban smoking in public spaces. That includes employers at indoor workplaces. The laws also require employers to take active measures to enforce the no-smoking bans, including posting signs and removing ashtrays. If smoking does take place, the employer and its officers and directors can be held liable.
Final Note: In most jurisdictions (Federal, Newfoundland and PEI are the lone exceptions), the indoor smoking ban must cover not just the fixed facility but also work vehicles used to carry workers.