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For normal home use, aerosol sprays are a small cancer risk. The best-documented issue is benzene contamination from the propellant, and the main fixes are good product choice and good airflow. Links in the text go to the source for each claim. A full list, grouped by section, is at the end. TL;DR Benzene is the real issue, and it is a contamination problem, not an ingredient problem. Some aerosol dry shampoos, antiperspirants, sunscreens and antifungal sprays were recalled in 2021–2022 after tests found benzene, which most likely came from butane, propane or isobutane propellants. Risk assessments put the extra cancer risk from typical use below standard safety benchmarks. Confidence that contamination happened: High. Confidence that occasional use causes measurable harm: Low. The stronger, proven harm from sprays is to the lungs, not cancer. A 10-country European study of 3,503 people (Zock et al., 2007) found that weekly use of cleaning sprays raised the risk of new asthma symptoms by 49% (relative risk 1.49). Another study from the same European survey links cleaning to faster lung function decline. Heavy work exposure (painters, hairdressers) carries a classified cancer hazard. Consumer cancer data are thin. Confidence: High for respiratory effects and occupational hazard; Low for consumer cancer risk. Several popular fears are not supported. Aluminum antiperspirants and parabens have no proven link to breast cancer. Talc is “probably carcinogenic,” but the human evidence is limited and is about powder use, not sprays. Overall confidence in this article’s core message: Medium-High (about 70%). Hazard vs. risk A hazard is something that can cause cancer. Risk is the chance it will, given how much you are exposed to and for how long. ...