New study links chemical sunscreens to birth defects

woman applying sunscreen
CC BY 2.0 Fort George G. Meade

Oxybenzone may be effective at filtering UV light, but it comes at a dangerously high cost to human health.

Chemical sunscreens have received a lot of press in recent months, with Hawaii, Palau, Aruba, Bonaire, and now Key West all banning their sale and use. There is growing concern over the toxicity of chemicals used in the formulas, primarily oxybenzone and octinoxate, and the harm they cause both to human and marine health.

These chemicals are used by sunscreen manufacturers to filter and absorb UV light, block out the sun's radiation, and extend the amount of time a person can spend in the sun; but in February 2019 the Food and Drug Administration delisted oxybenzone and 13 other petroleum-based UV sunscreen chemicals from being 'generally recognized as safe and effective.'

Haereticus Environmental Laboratory in Virginia has been a leading force in the research into chemical sunscreen's toxicity. Researchers from the laboratory have just published a study in the journal Reproductive Toxicology indicating a link between oxybenzone exposure and the formation of birth defects during the first trimester of pregnancy – specifically, a defect called Hirschsprung’s Disease. The following graphic explains more:

oxybenzone and birth defects© Haereticus Environmental Laboratory (used with permission)

The study authors strongly urge pregnant women to avoid using sunscreen products with oxybenzone in their first trimester, as well as women trying to conceive, since oxybenzone is a fat-soluble chemical that can linger in the body for weeks. Joe DiNardo, one of the study co-authors, said,

"A pregnant woman who follows the instructions for the recommended use of sunscreen products containing 6% oxybenzone (two 1-ounce application of sunscreen) could have concentrations of oxybenzone and fetal blood levels reach as high as 3,800 part per billion in the woman, and 384 parts per billion in the fetus. These concentrations of oxybenzone can potentially cause these toxic cellular changes, and give rise to Hirschsprung’s Disease."

A second paper, also published this week by the scientists at Haereticus, reveals the dangers of applying chemical sunscreens to children under the age of 5. A review of 169 sunscreen products labeled as safe for use on babies and children found unsafe levels of six common chemical UV absorbers – all of which are known endocrine-disrupting chemicals – when applied according to manufacturers' recommendations.

In an email to TreeHugger, researcher Craig Downs said that oxybenzone is a risk even when not applied directly.

"Oxybenzone that is contaminating swimming pools and beaches can be absorbed directly into the skin of pregnant women and children, increasing their exposure to oxybenzone and the risk associated with that exposure. I won’t let my own children get into public swimming pools or many beaches because the levels of oxybenzone and octocrylene can be dangerously high."

It is clear that we should not be using chemical sunscreens, and that physical sunblocks with minerals such as zinc oxide and titanium dioxide are a much safer choice. Fortunately there are a growing number of these on the market – and even some that won't make you look like Snow White. Check the EWG's guide to safe sunscreens for more info.

Better yet is the use of UV-blocking clothing, which Downs says should be the first line of protection against the sun. "UPF clothing is sunscreen that doesn’t wash off, has fantastic broad-spectrum UV protection, and can make the same marketing claims as sunscreens."

New study links chemical sunscreens to birth defects
Oxybenzone may be effective at filtering UV light, but it comes at a dangerously high cost to human health.

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