Radiation, solar and ultraviolet

Category

Radiation

Description

The sun is the major source of ultraviolet radiation (UVR), divided into UVC (100-280 nm), UVB (280-315 nm) and UVA (315-400). Of the solar UVR reaching the earth, 95% is UVA, and 5% is UVB. UVC is filtered out by the atmosphere. [Reference #1]

Sources/Uses

Workers exposed to sunlight and UVR include outdoor workers, welders, and workers exposed to germicidal UV light, lasers, and drying/curing processes. [LaDou, p. 137-8] See the TLVs for workers exposed to ultraviolet radiation from "arcs, gas and vapor discharges, fluorescent and incandescent sources, and solar radiation" to prevent burns and photokeratitis. [ACGIH]

Comments

Solar radiation is a known occupational carcinogen (outdoor workers) associated with increased risk for malignant melanoma and other skin cancers. [Siemiatycki, p. 326] UVR can also cause photokeratoconjunctivitis (welder's flash), cataracts, skin burns, and both photoirritant and photoallergic contact dermatitis (PICD and PACD). [LaDou, p. 185] Basal cell and squamous cell carcinomas of the skin, but not melanoma, correlate with cumulative exposure to UV light; [Wald, p. 245-6] "Two observations from epidemiological studies may help explain the paradox of the lack of association of melanoma with chronic sun exposure. First, outdoor workers are not at a substantially increased risk of melanoma; second, outdoor workers tend to have a higher-than-average ability to develop a tan. Outdoor workers tend to be constitutionally protected from solar skin damage and at a lower risk of skin cancer than workers in other occupations because of self-selection based on skin pigmentation." [Reference #1] See chemicals, drugs, plants, and foods in this database that can cause photoirritant and photoallergic contact dermatitis.

Reference Link #1

Biomedical References

Explanatory Notes

See the detailed tables in "Threshold Limit Values for Chemical Substances and Physical Agents." [ACGIH]

Reference Link #2

Skin burns

Established

Human carcinogen

Diseases

Occupational diseases associated with exposure to this agent:

• Cataract, chemical or radiation induced
• Melanoma
• Skin cancer