IOSH Controlling Risks 1 — Questions and Answers
Question 1: What is 'elimination' in the hierarchy of control?
- Using personal protective equipment
- Completely removing the hazard from the workplace (Correct answer)
- Replacing a hazardous substance with a less hazardous one
- Putting up warning signs
Correct answer: Completely removing the hazard from the workplace
Elimination means completely removing the hazard so that the risk no longer exists. For example, removing a trip hazard, stopping a dangerous process, or redesigning work so a hazardous activity is no longer needed. It is the most effective control.
Question 2: What is 'substitution' as a control measure?
- Training workers to use equipment safely
- Replacing a hazardous substance, process or equipment with a less hazardous alternative (Correct answer)
- Isolating the hazard from workers using physical barriers
- Providing respiratory protective equipment
Correct answer: Replacing a hazardous substance, process or equipment with a less hazardous alternative
Substitution involves replacing something hazardous with something less hazardous. For example, using a water-based paint instead of a solvent-based one, or using a less noisy machine. It is the second most effective control after elimination.
Question 3: What is an 'engineering control'?
- A control measure that relies on workers following procedures
- A physical control such as a guard, ventilation system, or enclosure that reduces exposure (Correct answer)
- A type of personal protective equipment
- A training programme for engineers
Correct answer: A physical control such as a guard, ventilation system, or enclosure that reduces exposure
Engineering controls use physical means to reduce or prevent exposure to hazards. Examples include machine guards, local exhaust ventilation (LEV), acoustic enclosures, safety interlocks, and handrails. They are preferred over administrative controls and PPE.
Question 4: What is an 'administrative control' measure?
- A physical barrier around a hazard
- A control that relies on procedures, training, signage, job rotation or scheduling (Correct answer)
- A type of PPE
- Eliminating the hazard entirely
Correct answer: A control that relies on procedures, training, signage, job rotation or scheduling
Administrative controls change the way people work rather than removing or physically controlling the hazard. Examples include safe systems of work, procedures, training, supervision, signage, job rotation, and limiting exposure time.
Question 5: Why is PPE considered the last resort in the hierarchy of control?
- Because it is the most expensive option
- Because it only protects the individual, can fail, and depends on correct use (Correct answer)
- Because workers prefer not to wear it
- Because it is not required by law
Correct answer: Because it only protects the individual, can fail, and depends on correct use
PPE is the least effective control because it only protects the individual wearing it, it can be uncomfortable, it may not be worn correctly, it can fail or degrade, and it doesn't reduce the hazard itself. Higher-level controls protect everyone.
Question 6: What is a 'safe system of work'?
- A system where no accidents have ever occurred
- A formal procedure based on systematic examination of work to identify hazards and define safe methods (Correct answer)
- A computer system for recording accidents
- An insurance policy covering workplace injuries
Correct answer: A formal procedure based on systematic examination of work to identify hazards and define safe methods
A safe system of work is a formal procedure resulting from a systematic examination of a task to identify all the hazards. It defines safe methods of working that eliminate those hazards or minimise the risks. It considers people, equipment, materials and the environment.
IOSH Controlling Risks 1
What is 'elimination' in the hierarchy of control?