Hazard Assessment

Worksite Hazard Assessments:

The Alberta Occupational Health and Safety Code (Part 2, sections 7 to 11) requires that a hazard assessment be done at ALL work sites (field, laboratory, workshop, office) to identify existing or potential hazards to the workers. This should be a written document prepared by the employer/supervisor in consultation with workers. Once identified, measures should be listed that can eliminate (preferred) or at least, to control the hazards. Control measures can include the use of engineered and administrative procedures that protect the worker. If these steps do not fully control the hazard, a final approach is to use Personal Protective Equipment (PPE).

Control Measures for Hazards: 1. Engineering Controls try to control exposure at the source and are applied first. These may include:
  • removal of the hazard
  • substituting a less hazardous material
  • enclosing the hazard (e.g. use of equipment guards, fume hood for volatiles)
2. Administrative Controls are applied next:
  • managing the process to avoid exposure; follow a written safe operating procedure (SOP)
  • training workers
  • control exposure by job rotation, rest breaks
  • regular inspection and maintenance

3. Personal Protective Equipment (PPE) is the last control measure to apply. These aim to control the exposure at the point of reception: e.g. use of gloves, respirator, eye protection, protective clothing. Use of PPE is the last resort to try and protect the worker after engineering and administrative controls have failed to limit the hazard.

In conducting a hazard assessment, it is often good to start by listing all the tasks that will be done, then identify the probable/potential hazards associated with the task and finally identify the control measuresthat will mitigate or eliminate the hazards.

Hazards may be grouped into four main categories and considering these may help you in hazard identification:
  • physical hazards: ergonomics, falls, trips, collisions, mechanical, electrical, noise, temperature
  • chemical exposure: toxins, corrosives, gases
  • biological agents: viruses, bacteria, protozoa and wildlife
  • psychological hazards: stress, fatigue, violence
Ranking the Hazards:
Not all hazards pose the same risk to workers. You can evaluate the hazard according to:
  • the frequency of exposure to the hazard
  • the magnitude or severity of damage that could occur (worst case)
  • the probability that an injury will occur
using a scale of low, medium or high (LMH) and the composite of all these rankings is a measure of the risk associated with an activity. Obviously a hazard ranked HHH needs attention more than one ranked LLL. The goal should be to eliminate or reduce the risk to an acceptable level. Certainly all unnecessary risks should be eliminated The ranking of hazards will depend on exactly how a task is being performed and what control measures are in place. Even with some controls applied, the risk may not be acceptable and the situation may need additional consideration.

Note: while the hazards and control measures may be similar for various tasks at the worksite, there may be subtle differences that can greatly affect the risk so when preparing a hazard assessment based on a previously written one, be sure that all the specifics of your situation are taken into account. Don't just cut and paste from another assessment without reviewing everything in detail. Hazard assessments should be reviewed from time to time if any changes in the procedure or circumstances have occurred and especially after an unexpected "event" has taken place.


Here are two examples to help illustrate the kinds of control measures that may be applied.

1. in a laboratory:
Task: preparing 1 liter of a solution containing 20% hydrochloric acid in water. The hazards associated with handling a 2.3L bottle of concentrated HCl include having acid contact the skin/face/eyes due to breakage/spillage/splashing and breathing in highly corrosive vapors.

Control measures could include:
Engineering Controls: working in a fume hood with the glass as low as practicable for handling the acid stock bottle; using a bottle carrier to move the bottle from the storage location into the hood.
Administrative Controls: if the worker is not experienced with handling strong acids, have a knowledgeable person supervise the operation. Have a written procedure outlining the sequence to follow to mix the acid with water. This is often called a Safe Operating Procedure or SOP and lists the steps that need to be followed in order to complete the task safely. The name of the SOP should be mentioned in the text of the control measures.
PPE: wearing a lab coat (buttoned up), plastic apron, disposable gloves, safety goggles and a face shield. If a spill occurred outside the fume hood, an appropriate respirator would be needed for cleanup.

2. In the field:
Task: unloading a quad from a truck. Hazards could include driving off the ramps, having a ramp move or break during use, having the quad flip over backwards.
Engineering Controls: have strong enough ramps that are anchored on the truck and the ground so they don't move; have ramps long enough so the slope isn't too steep; use a winch to raise/lower the quad without having to drive it on/off.
Administrative Controls: have a written procedure describing exactly how to unload the quad; have a second person to assist with the unloading and ensure that the wheels are centered on the ramps
PPE: operator wears sturdy boots, leather gloves and a helmet when driving a quad.

Here are some examples of field hazards and control measures that might be useful in preparing a hazard assessment for field activities.