Evaluate and Control The Hazards

After identifying the hazards in your lab, the next step is to properly evaluate and control the hazards. Be sure to check if your lab building has specific emergency safety features.


A risk assessment can help to determine the probability that an adverse event will occur and the consequence of that event. A risk assessment can reduce the likelihood that faculty, staff or students may be unnecessarily exposed to a laboratory hazard.  

Hazard Assessment

Supervisors are responsible for properly assessing the hazards in their individual lab areas. Safety staff are available to assist with conducting these assessments.

A proper evaluation includes the following:

  • Performing a comprehensive review of a specific hazard, such as a specific chemical or biological material to be used
  • Reviewing a hazardous activity or procedure to be performed, including the controls that will be used to prevent injury,
  • Documenting the review into a written Standard Operating Procedure,
  • Making sure specific protocols have gone through appropriate UVM review boards (IBC, IRB, IACUC), if necessary, and
  • Re-evaluating lab tasks when changes are made to current procedures.  


Contact Safety staff if you would like us to conduct a comprehensive review of your lab materials or activities. Always be sure to have proper controls in place before performing a lab experiment or procedure. 

Hierarchy of Controls

Traditionally, a hierarchy of controls is used to determine how to implement feasible and effective controls for any hazard.

Control methods at the top of the hierarchy are potentially more effective and protective than those at the bottom.  Following the hierarchy can lead to the implementation of inherently safer systems, where the risk of illness or injury can be substantially reduced. Always follow the order of this hierarchy when considering how to control any laboratory hazard.

Engineering Controls
Work Practices (also called Administrative Controls)  
Personal Protective Equipment
References for Best Safety Practices 


Can you eliminate the hazard? Eliminating the hazard means physically removing the hazard from the procedure or the work area. Eliminating the hazard is the most effective method of minimizing an exposure to any hazard.  However, elimination is not often a viable option.


  • Dispose of an old hazardous chemical,
  • Remove an extension cord from laying across a traveled path, or
  • Lock and Tag a dangerous machine out of service.


Substitution replaces a hazard with an action or material that is less hazardous. 

Examples: Replace ethidium bromide, a mutagen, with GelRed, SafeRed, or SYBR Safe. Be wary of marketing terms such as "natural", "green", etc.  Carefully review the Safety Data Sheet of any replacement product. Contact Safety staff if you are unsure if the replacement is actually a better choice.

Note: Do not dispose of these less hazardous ethidium bromide replacements in the UVM trash. Label and collect for them for proper lab waste disposal.

Engineering Controls

Examples of primary engineering controls used in laboratories include:

Engineering controls are used to remove a hazard or place a barrier between the user and the hazard. Engineering controls may be ducted and exhausted out of the building or may use a filter to capture aerosols or particles. Well-designed engineering controls can provide highly effective protection to the user.

The initial cost of an engineering control can often be higher than the cost of administrative controls or personal protective equipment. However, over the long term, operating costs are frequently lower.  Engineering controls often require some form of maintenance such as calibration of monitors and alarms, filter replacement and/or specific airflow certifications upon installation or annually.

Visit the general laboratory ventilation webpage, including task-oriented ventilation, for more information.

If you need/want to add an engineering control that affects part of any UVM building system (HVAC, electrical, plumbing), the control must be installed by UVM Facilities, Design and Construction (FD & C) services group or UVM's Physical Plant Department (PPD).

Work Practices

Work Practices are also called "administrative controls". They include altering the way in which a procedure is done, monitored and/or restricted.  


  • using proper labeling and signage to communicate the hazard to others
  • conducting monthly lab self-inspections to regularly eliminate any noticeable hazards
  • instituting a "buddy system" when hazardous work is being performed,
  • having an emergency plan: consider "What if...." Then, train lab users before an emergency happens,
  • relocating a piece of equipment so the flow of work can be done safely and more efficiently,
  • restricting the length of time that a person is exposed to noise, a particular substance or a specific activity,
  • enforcing rules about daily housekeeping,
  • performing regular equipment maintenance,
  • instituting strict personal hygiene practices,
  • establishing a Working Alone Policy,
  • requiring the use of Unattended Operations signage, or
  • creating a written standard operating procedure (SOP).

For more information on writing an SOP for your lab and to view some guidelines for specific chemical hazards, visit the Specific Hazard webpage.

As you can see, administrative controls are a crucial part of controlling any hazard.


Personal Protective Equipment

Personal protective equipment (PPE) is often referred to as the last line of defense.  As a control method, PPE has  proven to be less effective than other control measures. PPE is generally used with some form of engineering control. 

Proper PPE must be made available for an emergency response or cleanup procedure as well. Proper PPE increases the level of safety protection from a chemical, biological or physical hazard during an unexpected event.

Go here for more information about personal protective equipment.


Basic Lab Safety Practices

Resources for overall best safety practices



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