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4. Control Measures | Ultraviolet Radiation in the Workplace

  • ISBN: 978-1-4249-9714-5
  • Issued: August 1994
  • Revised: March 2009
  • Content last reviewed: June 2009
  • See also: Heat and Radiation Hazards

The following control measures can help to prevent the overexposure of workers to ultraviolet UV radiation. The measures used will depend on each situation.

Engineering Controls

  • UV radiation should be contained or confined to a restricted area when practicable.
  • UV radiation can be easily contained with opaque materials, such as cardboard or wood. Transparent materials, such as glass, PVC (polyvinylchloride), plexiglass and perspex, block UV radiation in varying degrees. Generally, carbonated plastics provide adequate UV protection. Some kinds of clear glass (including some kinds of window glass and optical glass) transmit significant amounts of UV-A radiation.
  • A high-power UV source should have interlocked access, so that it is shut off when the protective enclosure is open.

Administrative Controls

  • Whenever UV radiation cannot be contained or confined, worker exposure should be minimized by limiting exposure times and increasing the distance between workers and the sources. Measurements are required to determine safe working distances and exposure times.
  • Areas where exposure to UV radiation is possible should have appropriate warning signs.

Personal Protection

Workers exposed to UV radiation in excess of the above guidelines should use the following personal protective equipment:

  • UV-blocking safety eyewear (goggles, spectacles, face shields, welding shields, etc.) with side-shields where applicable,
  • long-sleeved, closely-woven clothing that covers as much of the body as practicable, and
  • sun-screen with a sun-protection factor (SPF) of 30 or higher and effective against UV-A and UV-B on all exposed skin.

Preventing Overexposure to UV Radiation From the Sun

In Ontario, during the midday hours on clear summer days, UV radiation from the sun can easily exceed the exposure limits quoted above. When practicable, the exposure of outdoor workers to solar UV radiation should be minimized by:

  • making use of natural or artificial shade, or
  • scheduling alternative tasks when the sun is most intense

While working in direct sunlight when UV levels are high, outdoor workers should:

  • limit the amount of time you work outdoors in the sun from 11 a.m. to 4 p.m.
  • seek shade as much as possible, especially during breaks
  • wear a wide brim hat (8 cm or more); attach a back flap and visor to a construction helmet
  • wear tightly woven clothing covering as much of the body as is practicable
  • apply broad spectrum sunscreen with a Sun Protection Factor (SPF) of 30 or higher on exposed skin. Reapply at noon and often if perspiring heavily
  • apply a broad spectrum lip balm with a SPF of 30 or higher
  • wear eyeglasses that effectively filter ultraviolet rays. The ANSI Z80.3–2001 standard for non–prescription sunglasses should be followed as applicable.

Note: The use of UV-safety measures should not lead to other safety risks--the risk of head injuries from using hats with inadequate impact protection, for example, or the risk of heat stress from wearing heavy clothing in hot environments.

What is to be Done When Workers Have Been Overexposed?

Provide First Aid:

  • For UV overexposure of the eye, place a sterile dressing over the eye and get medical attention.
  • For UV overexposure of the skin, apply cold water or ice to the skin burns and get medical attention.

Carry Out a UV Safety Audit:

  • Identify the sources and circumstances that produced the overexposure.
  • Discontinue their use to prevent other incidents.
  • Determine UV exposure levels and make sure that adequate controls are put in place.

How Should a Program to Prevent Overexposure of Workers be Organized?

  • Prepare a list of UV sources in the workplace. Note their wavelength range and output power (if applicable) and determine their hazard potential (see Table 1).
  • Review work processes and identify those that may cause UV exposure.
  • Have a UV radiation survey carried out by a qualified person. Determine exposure levels, allowable exposure times, safe viewing distances and the need for personal protective equipment.
  • Put in place adequate UV control measures (see Table 1).
  • Update your workplace UV-safety program as new sources are introduced.


2008 Threshold Limit Values (TLVs) for Chemical Substances and Physical Agents and Biological Exposure Indices (BEIs). American Conference of Governmental Industrial Hygienists (ACGIH). 1330 Kemper Meadow Dr., Cincinnati OH 45240.

American National Standards Institute Z80.3–2001 “Nonprescription Sunglasses and Fashion Eyewear — Requirements” 1819 L Street, NW, 6th Floor Washington, DC, 20036.

American National Standard Z136.1–2007 for Safe Use of Lasers. American National Standards Institute (ANSI). 11 West 42nd St., New York NY 10036.

For More Information

For more information about UV radiation and radiation protection in the workplace, please call the Radiation Protection Service at 416–235–5922.

Permission is granted to photocopy Ministry of Labour Guidelines. Please distribute them widely and post them where people will see them.

Note: This guideline gives advice on the prevention of overexposure to UV radiation in the workplace and sets out the occupational exposure limits that are enforced in Ontario workplaces by the Ministry of Labour. It cannot cover all possible situations. The requirements set out in the Occupational Health and Safety Act must be complied with and they should be referred to when this guideline is used.

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