Pressurized Paint Container Explosion — Why Isocyanate Training Cannot Be Optional

The Lid Flew Off — What Happens When You Don't Train for Designated Substances

Let's talk about what happened at Genaire Limited's aviation parts manufacturing facility in Niagara-on-the-Lake in July 2023. A worker who normally assisted with production was asked to assume painting duties — specifically, painting with a hazardous paint mixture that contained isocyanates, a designated substance under Ontario Regulation 860. The worker asked for training before starting. None was provided. The worker began painting on July 14, 2023. At the end of that first day, they had leftover paint mixture. Not knowing what to do with it — and having received no training on the regulatory requirements for isocyanate-based paints — the worker sealed the lid on the container and left it in the paint booth to reuse the next day. Ontario Regulation 860 requires isocyanate mixtures to be used within four hours of preparation. Any remainder must be safely disposed of. The sealed container sat over a long weekend. Pressure built up inside. On July 17, 2023, when the worker returned and tried to open the container, the lid flew off with force and struck the worker, causing serious injuries. A Ministry investigation found what the worker could have told them from day one: they had never been informed of the four-hour rule. They had never been trained on the safe handling requirements for isocyanates. They were assigned to a designated substance task and expected to intuit compliance with a regulation they'd never seen. Genaire pleaded guilty in Welland Provincial Offences Court and was fined $60,000 plus a 25% victim fine surcharge.

What the Law Requires

Ontario Regulation 860 — the Designated Substance Regulation for Isocyanates — exists precisely because isocyanate-based materials are hazardous in ways that are not obvious to someone unfamiliar with them. Section 7(1)(c) of Ontario Regulation 860, read together with Section 25(1)(c) of the OHSA, requires employers to ensure that prescribed measures and procedures for designated substances are carried out in the workplace. Basically, what this means is simple: if your workers handle isocyanate-based paints, coatings, or adhesives, they must be trained on the specific requirements of Ontario Regulation 860 before they touch the substance. The four-hour rule — use the mixture within four hours, safely dispose of any remainder — is one of those requirements. A worker who has never heard of it cannot be expected to follow it. The court found that Genaire had assigned a worker to a task involving a designated substance without providing any training on that substance. The worker requested training and was denied. The resulting injury was not a freak accident — it was the foreseeable consequence of a foreseeable gap. In the court's view, this was not an unfortunate coincidence — it was a fundamental failure to train before assigning. The $60,000 fine reflects the company's obligation under both the OHSA and Ontario Regulation 860 to ensure workers are competent before handling designated substances.

What Supervisors Must Do

• Before assigning any worker to a task involving a designated substance, confirm that the worker has received the required training under the relevant designated substance regulation
• Specifically for isocyanates: ensure workers know the four-hour use limit, how to safely dispose of leftover mixtures, and what to do if a sealed container shows signs of pressure
• If a worker requests training before performing a new task — especially a task involving hazardous materials — stop the assignment until training is provided; this request is a legal and moral signal that must be respected
• Conduct a walk-through of the painting area or work zone with newly assigned workers; confirm they understand storage, disposal, and emergency procedures before they begin
• Keep asking: 'Has every worker on this task been trained on the specific regulatory requirements for the substances they're handling — not just general hazardous materials awareness, but the specific regulation?'

What Employers Must Do

• Maintain a list of all designated substances present in your facility and ensure a training program exists for each one, aligned with the applicable Ontario designated substance regulation
• Specifically for Ontario Regulation 860 (Isocyanates): your training must cover the four-hour use rule, safe disposal of leftover mixtures, ventilation requirements, and emergency response for exposure or container failure
• Build a competency check into your task assignment process: before any worker is assigned to a designated substance task, their training record must be reviewed and confirmed
• Never allow a worker to begin working with a designated substance because they're available or because the task is urgent — training is a legal prerequisite, not a scheduling option
• Ensure that all substitute or relief workers are trained on designated substances before they fill in for regular staff
• Review your designated substance inventory and training records annually; if a substance is in your facility and a training program doesn't exist for it, create one before any worker handles it again

How to Use This Case in Your Workplace

This case is a valuable safety conversation starter. Use it during annual designated substance training sessions, supervisor training on work assignment decisions, and onboarding for any worker who will be assigned to paint, coat, or work with adhesive applications in your facility. Walk your team through the task and ask: 'If a production worker was asked to fill in for the painter today, would they know about the four-hour rule before touching the paint?' 'Does our training program for isocyanates cover storage and disposal — or just PPE and ventilation?' 'If a worker asked for training before starting a new task, what would actually happen — would they get it, or would we find a way to assign them anyway?' This case reinforces a simple message: Ontario Regulation 860 exists because isocyanate exposures cause serious, sometimes permanent injury. Untrained workers cannot protect themselves from hazards they don't know about. Training is not optional — it is the employer's legal duty and the first line of prevention.