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Alert: Ultraviolet Radiation from the Sun

  • ISSN: 1195-5228
  • Revised: March 2009
  • Content last reviewed: June 2009

Hazard Summary

People who work outdoors should avoid prolonged exposure to sunshine because of the damaging effects of ultraviolet (UV) radiation from the sun.

Excessive exposure to the sun's radiation over the years is a factor related to premature skin aging, skin cancer, and cataracts.

The UV levels are highest in spring and summer between 11 a.m. and 4 p.m. At noon on a clear summer day, for example, it can take only 15 minutes to cause a sunburn on unprotected fair skin.

To reduce the exposure of workers to ultraviolet rays while working in direct sunlight when UV levels are high, the following precautions are recommended:

  • 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 “Nonprescription Sunglasses and Fashion Eyewear — Requirements” should be followed as applicable

For information on the ANSI Z80.3–2001 “Nonprescription Sunglasses and Fashion Eyewear – Requirements” standard, visit

For further information on UV radiation please contact the Radiation Protection Service at 416–235–5922 or the Ministry of Labour office nearest you.

This Ministry of Labour Alert has no legal effect and does not constitute and is not a substitute for legal advice. If you require specific assistance with respect to the interpretation of a legislative provision and its potential application to you please contact your legal counsel.

Remember that while complying with occupational health and safety laws, you are also required to comply with applicable environmental laws.

Please photocopy Ministry of Labour Alerts, distribute them widely and post them where people will see them.