Description of sections

Environmental conditions

For an occupational group that has an asterisk (*) in the Environmental conditions ratings, refer to the Remarks section of that group for an explanation.


The work performed is carried out indoors in a regulated environment, indoors in an unregulated environment, outdoors or in a vehicle. In many occupations, the Main Duties may be performed in more than one location. Therefore, a group may have more than one Location code, for example:

  • firefighting and fire prevention duties
  • maintenance of interior/exterior of buildings
  • managing operations and paperwork of farms

L1 – Regulated inside climate

A normal controlled environment such as an office, hospital or school.

L2 – Unregulated inside climate

An inside work environment where the temperature or humidity may be considerably different from normal room conditions. In some groups, the nature of the duties affects the temperature or humidity of the work environment.


  • extracting coal/ore from underground mines
  • operating machines that press or blow molten glass
  • unloading stock into cold storage freezers
  • operating furnaces to melt metals for casting

L3 – Outside

An outdoor work environment where the worker is exposed to variations in weather conditions and seasonal weather patterns.


  • maintaining lawns
  • repairing buildings, roads, bridges and dams
  • operating power saws to thin and space trees
  • delivering mail

L4 – In a vehicle or cab

An interior space in any form of vehicle or in the cab of heavy equipment operated by the worker.


  • driving buses
  • operating cranes
  • providing service to passengers during flights
  • operating subway transit vehicles


Potential hazards to which the worker may be exposed. The codes provide an indication of the type(s) of hazard(s) most likely to be present in the workplace environment. They are not a measure of frequency, duration or degree of exposure to hazards, but an indication of the presence or absence of a particular hazard in the work environment.

H1 – Dangerous chemical substances

Exposure to any chemical that may endanger health through inhalation, absorption or ingestion, contact with skin or eyes, or any chemical with the potential for fire or explosion. Substances may be in forms such as solids, liquids, gases, aerosols or particles.


  • extracting coal (involves exposure to silica particles)
  • removing asbestos insulation from buildings
  • joining bricks with mortar (contains lime)
  • mixing pesticides to spray crops
  • painting building interiors

H2 – Biological agents

Exposure to infectious bacteria and viruses as a result of indirect contact with, or direct handling of, infectious materials or micro-organisms that may cause illness.


  • treating sick animals
  • performing autopsies
  • providing nursing care
  • investigating outbreaks of food and environment related diseases and poisonings
  • conducting microbiological tests and laboratory analyses

H3 – Equipment, machinery, tools

Working near or with equipment, instruments, machinery or power/hand tools that may be a potential source of accident or injury.


  • operating metal machining tools to shape metal
  • using hand and power tools to fabricate wood products
  • operating power saws to thin trees
  • performing surgical procedures

H4 – Electricity

Exposure to electrical circuitry, high tension wires, transformers or other equipment that may be a potential source of electrical shock.


  • installing or repairing electrical wiring, motors and generators
  • maintaining underground power transmission and distribution systems
  • operating semi-automatic electric arc welding equipment
  • repairing industrial electrical control systems and devices

H5 – Radiation

Exposure to ionizing radiation such as X-rays and radioactive substances or non-ionizing radiation such as radio frequencies and infrared, ultraviolet or visible light that may affect health adversely.


  • taking dental X-rays
  • preparing and administering radioactive drugs
  • operating welding equipment (ultraviolet)
  • controlling the flow of air traffic using radar monitors, radio and other equipment (radio frequencies)
  • conducting atmospheric research (visible laser light)
  • creating glass objects (infrared)

H6 – Flying particles, falling objects

Exposure to flying particles and falling objects in the work environment that pose the risk of bodily injury. Flying particles refer to particles such as wood chips, metal particles and rock chips generated by the handling, crushing, grinding, rapid impact or explosion of materials.


  • operating machining tools such as lathes/grinders
  • constructing underground installations in mines using hand and power tools
  • operating chain saws to fell and delimb trees
  • operating hoisting devices to load cargo onto ships
  • laying brick to construct or repair walls

H7 – Fire, steam, hot surfaces

Exposure to fire (rather than exposure to flammable substances that may ignite), to emissions of steam or to intensely hot surfaces that are potential sources of injury.


  • fighting fires
  • operating gas flame welding equipment
  • cooking food
  • forging metal items by hand or with forging machinery
  • tending industrial ovens/furnaces

H8 – Dangerous locations

Working in locations that are inherently treacherous and are potential sources of injury. Such work locations include construction sites, underground sites, erected support structures and marine environments.


  • building underground passageways in mines
  • installing roof shingles
  • washing exterior windows of buildings
  • commanding fishing vessels
  • operating underwater video, sonar, recording and related equipment


Work conditions that create disturbances but are not hazardous. In general, these conditions create discomfort, but are not direct sources of injury. In extreme instances, however, these conditions might cause injury.

D1 – Noise

Work that produces sufficient noise – constant or intermittent – to cause marked distraction or possible loss of hearing.


  • operating drilling equipment in underground mines
  • using power saws in logging operations
  • blasting rock surface in mining
  • operating heavy equipment for construction jobs
  • using firearms

D2 – Vibration

Work that produces an oscillating or quivering motion of the body.


  • operating jackhammers to break up pavement
  • driving tractors
  • operating drills to produce blasting holes in mines
  • shaping metal using power-forging machinery

D3 – Odours

The presence of noxious, intense or prolonged odours in the work environment.


  • cooking meals
  • colouring, waving and styling hair
  • preserving and sanitizing human remains
  • using industrial cleaning solutions
  • preparing standard cuts of meat, poultry and fish products for sale

D4 – Non-toxic dusts

The presence of non-poisonous airborne particles such as textile dust, flour, sand, sawdust and feathers in the work environment.


  • preparing dough or batter
  • cutting fur pelts or fabric for garments
  • operating woodworking machines
  • cleaning chimneys
  • removing poultry feathers

D5 – Wetness

Work that involves contact with water or other liquids.


  • digging ditches and trenches
  • sorting, cleaning and packing fish in ice
  • performing lifeguard duties
  • operating underwater sonar equipment
  • cleaning/disinfecting laboratory equipment
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