Legislated requirements put a premium on health and safety

Diver under water

Divers employed in Ontario are required to comply with the requirements of Diving Operations (Ontario Regulation 629/94) and the Ontario Occupational Health and Safety Act. The responsibility for compliance rests not only with the divers’ employer but also with the owner who contracts with the diving company.



The Act requires that an occupational diver and diving supervisors be competent persons. Competent person is defined as one who

  • (a) is qualified because of knowledge, training, and experience to organize the work and its performance;
  • (b) is familiar with the provisions of the Act and regulations that apply to the work; and
  • (c) has knowledge of actual or potential danger to health and safety in the workplace.

Training to a level equal to or exceeding the requirements of CSA Standard Z275.4-12 Competency Standard for Diving, Hyperbaric Chamber, and remotely operated vehicle operations is required by the Ministry of Labour (MOL). Documentation of training must be available at the dive site. Note: Recreational diving certification is NOT acceptable for occupational diving purposes in Ontario.

Each diver, dive supervisor, and diver’s tender must be qualified in first aid and cardiopulmonary resuscitation (CPR). Proof of qualification must be available at the dive site. Each occupational diver must be certified as medically fit to dive. A physician who is knowledgeable in diving and hyperbaric medicine must conduct the diving medical. The medical certification must also be available at the dive site.


Dive Supervisor

A knowledgeable and competent diving supervisor must supervise each occupational diving operation. The supervisor must be competent in the techniques being used, must remain on site, and must be in direct control of the diving operation.

Minimum Crew

A minimum crew of three must be present at each diving operation and must include a diver, a standby diver, and a diver’s tender. The standby diver or tender must be a competent diving supervisor. The minimum crew requirement will change according to depth, equipment used, degree of hazard, and other conditions.


Notice of Diving Operation

A "Notice of Diving Operation" must be submitted to the MOL before the diving operation starts. Refer to section 5 of the regulation for specific requirements.


SCUBA Restrictions

Restrictions have been placed on the use of self-contained underwater breathing apparatus (SCUBA) for occupational diving purposes.SCUBA cannot be used when a diver is

  • (1) The diving supervisor for a diving operation shall ensure that S.C.U.B.A. is not used by,
  • (a) a diver working near or in an operating underwater intake;
  • (b) a diver working near or in a pipe, tunnel, duct or other confined space;
  • (c) a diver working at a water control structure;
  • (d) a diver using any power tool, hoisting device, burning equipment or welding equipment;
  • (e) a diver placing any materials underwater in a way that poses a risk to the health or safety of the diver;
  • (f) a diver operating at depths in excess of 100 feet;
  • (g) a diver working in a diving operation to which Part XI applies;
  • (h) a diver handling an explosive device, unless the diver is a police diver engaged in a diving operation, including a diving operation for training purposes, that involves searching for and disposing of explosives; or
  • (i) a diver participating in a UXO diving operation, unless the diver meets the requirements of Clause 5 of CSA Standard Z275.6-11, “Unexploded Explosive Ordnance (UXO) and Munitions Diving”. O. Reg. 629/94, s. 36 (1); O. Reg. 32/14, s. 32.
  • (2) For the purposes of clauses (1) (a) and (b), a diver works near a thing where the proximity of the thing to the diver poses a health or safety risk to the diver. O. Reg. 629/94, s. 36 (2).

Surface-supplied diving equipment must be used in place of SCUBA when any of the above prohibitions apply.


Depth Restrictions

SCUBA must be limited to a depth of 100 feet. The use of air as a breathing medium is restricted to 165 feet. Beyond 165 feet, the diver must use an appropriate breathing mixture. Before the diving operation begins, the MOL must be notified of the intention to use such a mixture.

Safe Dive Procedures

Every employer engaged in diving operations must prepare a site-specific, safe diving operational plan and contingency plan. These procedures must be based on a comprehensive evaluation of diving hazards and be available at the dive site.


Standby Diver

A standby diver must be on the dive site at all times and be able to render assistance while diving is in progress. The standby diver must be able to enter the water immediately if required.

Specific Diving Hazards

This requirement deals specifically with the requirements for lockout, hazardous mechanisms, intakes, pipes, tunnels, and contaminated environments.


Owner Responsibility

An owner who contracts with a diving company must provide the company with any information necessary to control hazards. The owner must also ensure that diving activities are coordinated and supervised and that a "Notice of Diving Operation" has been submitted to the MOL before work begins. These and other requirements are spelled out in sections 4.1-10 of the regulation under duties of Employers, Constructors and Owners.

For further information, contact the nearest MOL office or the MOL Provincial Diving Specialist.