When evaluating the risks associated with specific hazards, the results of this evaluation should guide the researcher in the selection of risk management techniques including elimination, substitution, engineering controls, administrative controls, and personal protective equipment. This is known as the Hierarchy of Controls.
Elimination and Substitution
The most preferred method of controlling risk is to eliminate the hazard altogether. In most cases, elimination is not feasible and when possible, substitution is the best approach to hazard mitigation. When possible, substitute less hazardous agents in place of their more hazardous counterparts. This also applies to conditions and activities. Examples include substituting toluene for benzene, non-lead-based paints for lead-based ones, or SawStop table saws for existing traditional table saws.
Engineering controls consist of a variety of methods for minimizing hazards, including process control, enclosure and isolation, and ventilation.
- Process controls involve changing the way that a job activity is performed in order to reduce risk. Examples of this include using wet methods when drilling or grinding or using temperature controls to minimize vapor generation.
- Enclosure and isolation are targeted at keeping the chemical in and the researcher out, or visa versa. Glove boxes are a good example of enclosure and isolation. Interlock systems for lasers and machinery are other good examples of isolating processes.
- The most common method for ventilation in research laboratories is localized exhaust systems. Fume hoods, snorkels, and other ventilation systems are discussed at length in the Laboratory Equipment and Engineering Controls section of this site.
Administrative controls are controls which alter the way work is performed. They may consists of policies, training, standard operating procedures/guidelines, personal hygiene practices, work scheduling, etc. These controls are meant to minimize the exposure to the hazard and should only be used when the exposure cannot be completely mitigated through elimination/substitution or engineering controls.
Personal Protective Equipment (PPE)
PPE should always be used as a last line of defense and is an acceptable control method when engineering or administrative controls cannot provide sufficient protection. PPE may also be used on a temporary basis while engineering controls are being developed. See the standalone PPE section of this site for more information.