Biological Hazard

Biohazards and Eye Safety

April 23, 2020

Safety eyewear is not only required for eye protection against dust, dirt, flying debris, and other projectiles in your eyes, it’s important when working around biological agents. Biohazards in the workplace create a risk of exposure to infectious agents such as bacteria and viruses and those that are bloodborne.

Infectious disease can be transmitted by a range of mechanism, but the membrane of the eye is an important route of entry. Bacteria and viruses can cause conjunctivitis and systemic infections such as herpes. Systemic infections associated with bloodborne viruses can include Hepatitis B and C, and HIV. The infectious agent can be introduced directly into the eye from blood splashes or respiratory droplets produced by coughing or sneezing. They can also be introduced into the eye from hand-eye contact or other contaminated objects that may touch the eye. Health Canada recommends eye protection for a variety of potential exposure settings where workers may be at risk of acquiring infectious diseases via the ocular route of entry.

Employees who work in environments where biological agents are present need to learn about the hazards and the associated risks and familiarize themselves with the types of appropriate eye protection, their characteristics and applicable use. Workers should understand that regular prescription eyeglasses and contact lenses are not considered eye protection. Safety eyewear provides an effective control from exposure to infectious materials and needs to be used in conjunction with other personal protective equipment (PPE) such a protective clothing, gloves and respiratory protection.

Safety eyewear needs to be selected based on the specific nature of the work and related tasks being completed and the potential circumstances of exposure. When selecting safety eyewear, consideration needs to be given to other PPE needed to ensure the entire ensemble works together to provide optimum protection. There is wide variety in the types of protective eyewear, and appropriate selection should be based on a number of factors:

  • The nature and extent of the hazard.
  • Eye protection must be comfortable to increase wearer use and compliance.
  • It needs to allow for sufficient peripheral vision and must be adjustable to ensure a proper fit.

To ensure all employees are adequately protected it may be necessary to provide a range of sizes, types, and styles. Prescription safety eyewear is properly fitted through the Eyesafe program. The basic types of safety eyewear include safety glasses, goggles, face shields and full-face respirators. Each of these is discussed below in the context of protection from biohazardous agents.

Safety Glasses

Safety glasses provide impact protection, but do not provide the same level of splash or droplet protection as goggles, face shields and full-face respirators. The reason for the performance difference is that with safety glasses there is a gap between the protective eyewear and the face. Safety glasses should not be used for protection in biohazardous work environments.


Safety goggles provide the same broad protection as safety glasses, but they have a tight-fitting seal to the face. Safety goggles provide protection from splashes of biohazardous liquids, and come in three forms:

  • Direct-vented goggles have front-facing vents that improve air circulation and reduce fogging, but they allow for air flow directly into the goggle and are not recommended for biohazardous atmospheres.
  • Indirect vented goggles have covered vents and provide protection from splash entry by liquids. Air flow through the covered vents is restricted by the vent cover. The covered vents ensure that there is no direct straight-line passage from the exterior to the interior of the goggle preventing a liquid splash from entering the goggle.
  • Non-vented goggles have no venting of any kind and offer protection against all hazard types.

Indirect vented and non-vented goggles provide protection against droplets. These two types of goggles are preferred for environments where the biohazardous agent may be directly splashed or as airborne droplets. For ANSI approved goggles they will be marked with the D3 indicating they have met the splash and droplet penetration performance standard and are approved for protection against biohazards.

Face Shields

Face shields may be used as an added protection with goggles as they provide protection against inadvertent exposure by splash or droplets to the eyes, nose and mouth by a sneeze or directional cough and can be used in conjunction with goggles. Face shields should have a crown and wrap around the face all the way to ears to ensure a splash cannot reach the eyes. Face shields provide better face and eye protection from splashes and sprays. They may be disposable of re-usable.

Full-face Respirators and Powered Air Purifying Respirators

Full-facepiece respirators and powered air-purifying respirators (PAPRs) provide integrated respiratory protection and protection for the eyes and face. The selection of this type of PPE is typically based on an assessment of the respiratory hazard in an infection control situation, but also provides optimal eye protection. They provide the best protection from splash and droplet exposure of biohazardous agents to the eyes, nose and mouth and are the preferred control against potentially infectious disease causing agents.

Compatibility of the multiple types of PPE is an important consideration. Safety goggles may interfere with some types of respiratory protection and face-shields may not fit comfortably over all respirators. Once the workplace hazard has been fully characterized, an integrated program of PPE can be established. Full-facepiece respirators or powered air-purifying respirators may provide the optimal solution. In any situation where combinations of PPE may be required, judicious selection of complementary PPE is important to allow for proper protection.

After use, PPE must be considered contaminated by biohazardous sprays, splashes, or droplets. Hand contact of the contaminated PPE may spread the contamination. Donning and doffing of PPE needs to be completed considering this possibility. Non-disposable PPE, including eye protection, should be placed in a designated receptacle for subsequent cleaning and disinfection. The sequence of PPE removal should follow a defined regimen that should be specifically developed to take into consideration the need to remove other PPE, and that it is generally not disposable and must be disinfected before reuse. Where possible, each individual worker should be assigned their own eye protection to ensure appropriate fit and to minimize the potential of exposing the next wearer. Eye protection can be collected, disinfected, washed, and then reused.

Specific procedures for cleaning and disinfecting used patient care equipment should be followed for reprocessing reusable eye protection devices. Manufacturers may provide guidance on the most effective means of disinfecting their respective products. Contaminated eye protection devices should be reprocessed in an area where other soiled equipment is handled. Eye protection should be physically cleaned and disinfected with the approved disinfectant, rinsed, and allowed to air dry. Gloves should be worn when cleaning and disinfecting these devices.
Employee exposure to biohazards can be a serious issue, and safety eyewear needs to be included as a control strategy in biohazard areas to complement other PPE needed. Care needs to be taken in the selection, use and care of personal protective equipment, including safety eyewear.

Glyn Jones is a partner at EHS Partnerships Ltd. in Calgary. He is a consulting occupational health and safety professional with 30 years of experience. He is a regular safety conference speaker in Canada, and he provides program design and instructional support to the University of New Brunswick’s OHS certificate and diploma programs.

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