Fast facts
| Trade code | 253H |
|---|---|
| Sector | Construction |
| Classification | Voluntary trade |
| Certifying exam | Required (O. Reg. 876/21, s. 3) |
| Apprentice to journeyperson ratio | Not subject to a ratio |
| Red Seal trade | No |
| Active apprentices in Ontario | 212 (reported in Ontario's apprenticeship dataset) |
| Approved sponsors | 1 |
| Certifying body | Skilled Trades Ontario |
Last verified August 20, 2026 against the sources listed below.
What does a hazardous materials worker do?
A Hazardous Materials Worker identifies, removes, packages, transports and disposes of hazardous materials such as asbestos, mould, lead, mercury, and other biological harzards.
Skilled Trades Ontario describes the work of this trade as follows:
- mobilizes site enclosures
- pre-cleans work areas
- builds work area enclosures
- sets up decontamination chambers and waste chutes
- removes and cleans hazardous material
- dismantles work area enclosures and decontamination chambers
- performs post tear-down clean
- de-mobilizes site enclosures
- performs routine inspections
How long is the hazardous materials worker apprenticeship?
The in-school portion of this apprenticeship runs to 1 level. Skilled Trades Ontario does not publish a total hour requirement for this trade on its trade page; confirm the current requirement in the trade's apprenticeship training standard before signing an agreement.
What do you study in school for the 253H?
The in-school portion covers, but is not limited to:
- worker protection and hygiene practices
- biological hazards
- hazard protection and equipment
- physical hazards
- site isolation
- asbestos types 1, 2 and 3
- abatement operations
- environmental protection
- inspections
Is hazardous materials worker a compulsory trade in Ontario?
No. Hazardous Materials Worker is a prescribed trade under section 1 of O. Reg. 876/21, but it is not on the compulsory list in section 2. That means you can legally work in this trade in Ontario without holding a Certificate of Qualification. Certification is voluntary and serves as formal proof of competency to employers and clients.
Voluntary classification only covers certification under the Building Opportunities in the Skilled Trades Act. Specific work within the trade can still require separate licences or permits under other Ontario statutes, so confirm the rules for the actual work being done. The 23 trades where certification is mandatory are on the compulsory trades list.
How do you become a hazardous materials worker in Ontario?
The apprenticeship pathway for this trade is administered by Skilled Trades Ontario under section 14 of the Building Opportunities in the Skilled Trades Act, 2021:
- Find a sponsor and register a training agreement. An employer or union sponsor takes you on and the training agreement is registered with the ministry.
- Complete the on the job and in school training. The skills are set out in the trade's Apprenticeship Training Standard, signed off by your sponsor as you demonstrate them, alongside levels of in school theory at a training delivery agent.
- Receive your Certificate of Apprenticeship. Skilled Trades Ontario issues it when the program is complete.
- Pass the certifying exam. This trade has a certifying exam under O. Reg. 876/21, s. 3. Passing it earns the Certificate of Qualification, the voluntary proof of qualification for this trade.
The exact training standard, current curriculum and program details are on the Skilled Trades Ontario page for Hazardous Materials Worker. On the job hour requirements vary by trade and are not published on this page yet; confirm them in the training standard before signing an agreement.
Is the 253H a Red Seal trade?
No. Hazardous Materials Worker is an Ontario prescribed trade but is not part of the Interprovincial Red Seal Program, so an Ontario credential in this trade does not carry automatic recognition in other provinces. Workers moving to another province should check that province's own trade classification.
Already experienced? The Trade Equivalency Assessment
Workers with experience from outside Ontario's apprenticeship system, or from another country, can apply for a Trade Equivalency Assessment instead of starting an apprenticeship. Approval requires verifiable evidence of competency in the trade's Training Standard and experience at least equal to the trade's total training time; if approved, you challenge the certifying exam directly. The assessment costs $235 plus HST, and a reassessment with new evidence costs $100 plus HST, per Skilled Trades Ontario's Trade Equivalency Assessment page.
Certification is not the only paperwork
A Certificate of Qualification covers the person. Running a business in the trade carries its own obligations: many Ontario municipalities require a contractor licence on top of personal certification, and construction employers must complete WSIB registration before work begins. Both are indexed on our sister site: municipal contractor licensing requirements by city and WSIB Form 1000, registration of constructors and employers, on Ontario Trade Registry.
Where can you train as a hazardous materials worker in Ontario?
| Private training providers | 3 |
|---|---|
| Approved sponsors | 1 employers registered to train apprentices |
| Apprentices in training | 212 |
Counts are from Ontario's published apprenticeships dataset. A sponsor is the employer or union that registers and trains the apprentice; you need one before an apprenticeship can start.
How dangerous is construction work in Ontario?
Ontario does not publish injury figures per trade, only by sector. In 2024 the Ministry of Labour recorded 18 worker fatalities and 442 critical injuries under the construction health and safety program. See the ten-year counts and what they leave out.
Related Ontario trades
Other construction sector trades with certification records on this registry:
Official verification sources
- RegulationO. Reg. 876/21, Prescribed Trades and Related Matters (e-Laws)
- Certifying bodySkilled Trades Ontario: Hazardous Materials Worker
- ActBuilding Opportunities in the Skilled Trades Act, 2021 (e-Laws)
- Participation dataOntario open data: Apprenticeships dataset
Classification, exam requirement and ratio status on this page are read directly from O. Reg. 876/21 as consolidated on e-Laws, not from secondary summaries. Facts not yet verified against a primary source are marked as not published rather than estimated.