Ultraviolet (UV) rays are a part of sunlight that is an invisible form of radiation. UV rays can penetrate and change the structure of skin cells. There are three types of UV rays: ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC). Scientists believe UVA radiation can damage connective tissue and increase a person’s risk for developing skin cancer. UVB rays penetrate less deeply into skin, but can still cause some forms of skin cancer. Natural UVC rays are absorbed by the Earth’s atmosphere and do not pose a risk to workers.

Risky conditions

Sunlight exposure is highest during the summer and between 10 a.m. and 4 p.m. Snow and light-colored sand reflect UV light and increase the risk of sunburn. At work sites with these conditions, UV rays may reach workers’ exposed skin from both above and below.

Workers are at risk of UV radiation even on cloudy days. Plus, many drugs increase sensitivity to sunlight and the risk of getting sunburn. Some common ones include thiazides, diuretics, tetracycline, doxycycline, sulfa antibiotics, and nonsteroidal anti-inflammatory drugs, such as ibuprofen.

Risks of UV radiation

Sunburn is something we’re all familiar with. Years of overexposure to the sun lead to premature wrinkling, aging of the skin, age spots, and an increased risk of skin cancer. In addition to the skin, sunburned eyes become red, dry and painful, and feel gritty. Chronic exposure of eyes to sunlight may cause pterygium (tissue growth that leads to blindness), cataracts, and perhaps macular degeneration, a leading cause of blindness.


  • Red, warm and tender skin
  • Swollen skin
  • Blistering
  • Headache
  • Fever
  • Nausea
  • Fatigue

The pain from sunburn is worse 6-48 hours after sun exposure.

Seek medical attention for:

  • Severe sunburns covering more than 15 percent of the body
  • Dehydration
  • High fever (>101°F)
  • Extreme pain that persists for longer than 48 hours

Skin Cancer types include: Basal Cell (Can usually be removed by excision or topical treatments. If diagnosed and treated early, basal cell cancers can be cured.); Squamous Cell (Can usually be removed by excision or topical treatments. If diagnosed and treated early, squamous cell cancers can be cured.); Melanoma (Malignant melanoma carries significant, even fatal, implications.)

What to watch for:

  • Irregular borders on moles (ragged, notched, or blurred edges).
  • Moles that are not symmetrical (one half doesn’t match the other).
  • Colors that are not uniform throughout.
  • Moles that are bigger than a pencil eraser.
  • Sores that bleed and do not heal.
  • Itchy or painful moles.
  • Red patches or lumps.
  • New moles.

Recommendations for employers

To protect workers from exposure to UV radiation:

  • When possible, avoid scheduling outdoor work when sunlight exposure is the greatest
  • Provide shaded or indoor break areas
  • Provide training to workers about UV radiation including:
  • Their risk of exposure
  • How to prevent exposure
  • The signs and symptoms of overexposure

Recommendations for workers

Follow these recommendations to protect against UV damage:

  • Wear sunscreen with a minimum of SPF 15.

• SPF does not refer to protection against UVA. Products containing Mexoryl, Parsol 1789, titanium dioxide, zinc oxide, or avobenzone block UVA rays.

• Sunscreen performance is affected by wind, humidity, perspiration and proper application.

  • Throw away old sunscreens; they lose their potency after 1-2 years.
  • Apply sunscreens liberally (a minimum of 1 ounce) at least 20 minutes before sun exposure.

• Give special attention to covering the ears, scalp, lips, neck, tops of feet and backs of hands.

  • Reapply sunscreens at least every two hours and each time a person gets out of the water or perspires heavily.

• Some sunscreens may lose efficacy when applied with insect repellents, necessitating more frequent application when the two products are used together.

  • Dark clothing with a tight weave is more protective than light-colored, loosely woven clothing.
  • High-SPF clothing has been developed to provide more protection for those with photosensitive skin or a history of skin cancer.
  • Wear wide-brimmed hats and sunglasses with almost 100-percent UV protection and with side panels to prevent excessive sun exposure to the eyes.

Source: Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH) Workplace Safety & Health Topics, UV Radiation, www.cdc.gov/niosh/topics/uvradiation/