Reference summary — not medical advice or a personal risk estimate.
Solar UV radiation (sunlight)
Quick answer
Classified as Group 1 — carcinogenic to humans, based on sufficient evidence in humans. On skin and eyes. Time spent in sunlight without protection; highest exposure midday and at higher altitudes or lower latitudes.
Summary
Ultraviolet radiation from the sun is associated with melanoma and other skin cancers.
Detail
Solar UV radiation is Group 1 with sufficient evidence for melanoma and non-melanoma skin cancers. WHO and the major cancer-prevention bodies (including Cancer Council Australia, which leads on UV guidance) recommend limiting midday sun exposure, seeking shade, wearing protective clothing and broad-brim hats, using UV-blocking sunglasses, and applying broad-spectrum sunscreen (SPF 30 or higher) reapplied every two hours on uncovered skin.
What's not established
This classification is based on sufficient evidence in humans that this factor can cause cancer. It does not establish a safe exposure threshold, your personal risk, or how this factor's risk compares in size to other Group 1 agents — hazard classifications are not ranked by magnitude.
Regional relevance
global
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
NCI
NCI — Cancer Risk Factors: Sunlight
IARC
IARC Monographs — Classifications by Cancer Site, Vols 1–140
Supporting sources
Canadian Cancer Society
Canadian Cancer Society — Reduce your risk
ACS
ACS — Known and Probable Human Carcinogens
Cancer Research UK
Cancer Research UK — Causes of cancer and reducing your risk
IARC / WHO — European Code Against Cancer
European Code Against Cancer (5th edition) — 14 ways you can help prevent cancer
NTP
NTP — Report on Carcinogens (US National Toxicology Program)
Cancer Council Australia
Cancer Council Australia — Causes of cancer
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.