A simple question — what sunscreen do you use? — has become surprisingly controversial in the pool and spa industry.

In a March social media discussion among pool service professionals, what began as a request for sunscreen recommendations quickly turned into something else entirely. Instead of brand suggestions, the responses leaned toward avoidance. Some were blunt: “None.” Others went further: “Sunscreen causes cancer faster than the sun.”

Actual product recommendations were rare. Long sleeves, hats, and staying covered came up repeatedly. Sunscreen — long treated as standard protection for outdoor work — was often dismissed outright.

For a growing number of outdoor professionals, sunscreen is no longer a given. It’s a question.

Why? To understand that, it helps to separate what’s known from what’s assumed.

What We Know About Sun Exposure

The most firmly established fact is that ultraviolet (UV) radiation causes skin cancer. Long-term exposure damages skin cells through direct DNA injury and by weakening the skin’s immune defenses. That damage accumulates over time.

Skin cancers fall into two main categories. Melanoma is less common but more dangerous, with the potential to spread quickly and become fatal. Non-melanoma skin cancers — primarily basal cell carcinoma and squamous cell carcinoma — are far more common and typically less aggressive, but they can still become serious if untreated.

The link between UV exposure and these cancers is not debated. It is one of the most well-established relationships in cancer research.

Outdoor Work and Elevated Risk

For people who work outside, that risk is not theoretical.

Large studies consistently show that outdoor workers experience higher rates of skin cancer, particularly squamous cell carcinoma. In practical terms, the risk is often about 1.5 to 2.5 times higher than for indoor workers, depending on geography and lifetime exposure.

The relationship with melanoma is less consistent — likely because melanoma is more strongly tied to intense, intermittent exposure rather than continuous exposure — but cumulative skin damage is clearly higher in those who spend their careers outdoors.

What We Know About Sunscreen

Against that backdrop, sunscreen’s role — reducing UV exposure — has been studied in both controlled trials and long-term population research.

One of the strongest pieces of evidence comes from a randomized controlled trial conducted in Queensland, Australia. The study began in 1992 and followed participants assigned either to daily sunscreen use or discretionary use. The sunscreen used was typical of the time — broad-spectrum SPF 16, primarily chemical filters.

After more than a decade of follow-up, the group assigned to daily use had roughly half the melanoma rate of the discretionary-use group. Published in 2011, the study remains one of the clearest demonstrations that sunscreen can reduce cancer risk.

Other large-population studies in Australia and Scandinavia have found similar trends. Regular sunscreen users tend to show melanoma rates about 25 to 30 percent lower than non-users.

These studies are not perfect. People who use sunscreen may stay in the sun longer or may use other protective measures. But when multiple lines of evidence point in the same direction, researchers take that seriously.

There is broad agreement in the medical community: Sunscreen reduces skin cancer risk.

Where the Concerns Originate

So where does the skepticism about sunscreen among pool professionals come from?

Some sunscreen ingredients have been identified in laboratory settings as potential endocrine disruptors or possible carcinogens. Studies have also shown that certain ingredients are absorbed into the bloodstream during normal use.

The concern follows naturally: If these substances enter the body, could they cause harm over time?

Years of research have sought the answer to this question.

So far, the answer is no. There are no clinical or population studies showing that sunscreen causes cancer, despite decades of widespread use.

Rising skin cancer rates are better explained by longer lifespans, increased cumulative sun exposure, and improved detection — not sunscreen.

Sunscreens fall into two main categories. Mineral sunscreens — often called physical sunscreens — use zinc oxide or titanium dioxide to sit on the skin and reflect or block UV radiation. Chemical sunscreens — sometimes called organic filters — use compounds such as oxybenzone, avobenzone, octocrylene, octinoxate, and homosalate to absorb UV energy and convert it into heat. Early sunscreens often relied on PABA (para-aminobenzoic acid), a UVB absorber largely phased out due to staining, skin irritation, and a relatively high rate of allergic reactions.

Both types reduce UV exposure, but they differ in how they interact with the body and in how much is known about their long-term safety.

What Absorption Studies Found

The current debate largely centers on chemical (organic filter) sunscreens. Studies published in The Journal of the American Medical Association in 2019 and 2020 found that several common sunscreen ingredients are absorbed through the skin and can be detected in the bloodstream after normal use.

These studies answered one question clearly: The ingredients do enter the body.

To evaluate what that means, the U.S. Food and Drug Administration uses a very low threshold — a screening level based on measured blood concentrations — to determine when additional safety testing is needed.

This threshold is not a safety cutoff. It does not indicate danger. It simply signals that more data is required.

Exceeding that level does not mean an ingredient is harmful. It means it has not yet been studied enough to rule out long-term effects.

That distinction — between detection and demonstrated harm — is central to the discussion.

The Ingredients Behind the Concerns

Several ingredients are frequently cited: Oxybenzone has shown hormonerelated activity in laboratory and animal studies, meaning it can weakly mimic or interfere with hormones under certain conditions. These effects occur at exposure levels far higher than typical sunscreen use and have not been observed in human studies.

Octocrylene can degrade into benzophenone, a possible carcinogen, particularly in older or improperly stored products. This is primarily a storage issue, not a risk from fresh sunscreen.

Octinoxate and homosalate are also absorbed and remain under review due to limited long-term safety data. Concerns are based largely on laboratory findings rather than observed effects in humans.

Why Mineral Sunscreens Are Different

Mineral sunscreens present fewer uncertainties.

Zinc oxide and titanium dioxide remain on the surface of the skin and are not meaningfully absorbed. Studies show that particles stay within the outermost layer of the skin.

The primary caution relates to spray formulations containing titanium dioxide, where inhalation — not skin exposure — is the concern.

What This Looks Like in the Field

For pool and spa professionals, the issue is not theoretical. It’s practical.

Sunscreen wears off. It washes away. It gets skipped on busy days. In real working conditions, consistency is a challenge.

That’s why protection works best as a system — long sleeves, hats, shade when available, and sunscreen filling the gaps.

The all-or-nothing approach showing up in some conversations doesn’t reflect how protection actually works in the field.

What It Comes Down To

We know the sun causes cancer. We have strong evidence that sunscreen reduces that risk. We do not have evidence that sunscreen causes cancer in people.

At the same time, questions about certain ingredients remain under study, and that uncertainty is enough to change behavior for some.

For outdoor professionals, the decision is not just about what to use.

It’s about what information to trust — and how to balance a known risk against a potential one that has not been shown to cause harm.

For an industry that works in the sun every day, that distinction matters.