Benzene in Sunscreen

Carcinogens Found in Over 78 Sunscreen Products 

The safety of sunscreens has recently been brought up to question. A recent study by Valisure, a for-profit research facility, found that 78 tested sunscreens contained a known carcinogen: benzene.⁴ Valisure has been known for recently releasing data about detectable benzene in hand-sanitizers as well as toxic levels of NDMA in the popular anti-acid, Zantac.

What Is Benzene?

According to the CDC, benzene is a chemical that is a colorless or light-yellow liquid at room temperature and highly flammable. Benzene is also found in many daily use products including oil, plastics, and rubbers.⁴

Benzene has been recognized by the World Health Organization as a “Group 1 compound that should not be employed in the manufacture of drug substances because of unacceptable toxicity.”⁴ It has also been reported as a cancer-causing agent for humans.

The FDA states if “use is unavoidable to produce a drug of therapeutic effect, then the levels of benzene should not surpass 2 ppm (parts per million).⁴ Many of the sunscreens examined had traces of benzene as much as high as 6 ppm. 

Can Benzene Be Absorbed into the Blood? 

Because benzene is a known carcinogen and is found in everyday exposures such as gasoline, a study was conducted to estimate the absorption of liquid benzene in human skin. The authors used an experimentally determined dermal flux value absorbed through the hands for one hour over the course of 40 years. They found that even at 0.1% benzene absorption, long term exposure can lead to a 1.5 times increased risk of leukemia.²

Benzene has also been linked to a wide range of adverse noncancerous effects including changes in the functioning of respiratory, nervous, immune, hematological, hepatic, renal, cardiovascular, and reproductive systems. So even with small concentrations of benzene, long term complications can be detrimental. This all is dependent on how well sunscreen can penetrate the skin and into the bloodstream. 

Sunscreen Absorption in the Bloodstream

The penetration of sunscreen into the bloodstream was studied at the FDA. A randomized study looked at six main active ingredients used in different combinations in sunscreens: avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate. 

Of 48 healthy participants with varying Fitzgerald classification skin types, 44 completed the study. The participants were randomly divided into 4 groups and each group tested either lotion, aerosol, non-aerosol, and pump spray formulations, all of which included the 6 chemicals.³ The participants were told to apply different types of sunscreens with the active ingredients to 75% of their body over a course of 21 days.³

When plasma concentrations for the 6 active chemicals were tested, avobenzone was found to be the highest concentration at 7.1 ng/mL, but all 6 exceeded FDA thresholds of 0.5 ng/mL.³ Although the safety threshold was exceeded, the FDA upholds their recommendation to continue to use sunscreen, as the risks remain uncertain.

How Was Benzene Measured in the Valisure Study? 

Valisure utilized gas chromatography and detection of benzene with mass chromatography. They tested 294 batches of sunscreen and after sun care products from 69 different brands.⁴ The results are listed in the table below:

For reference, a benzene level >2.0 is not recommended by the FDA due to risk of carcinogen. 

Which Sunscreens Are Considered Safe According to the FDA?

There were a handful of sunscreens in which little to no benzene was detected. This batch was considered safe in accordance with the FDA guidelines. The sunscreens have been noted in the chart below:

Which Sunscreens Had No Detectable Benzene?

In the 297 sunscreens tested, 216 had no detectable benzene.⁴ The general trend shows most of the sunscreens that had a trace of benzene were sunscreen sprays. Although a thorough investigation into the difference between aerosol sunscreen vs. lotion is lacking, a theory has been posed that the contamination may be a reaction of active ingredients in sunscreen and a propellant.

Beyond that, aerosol sunscreens tend to be less absorbed, so the actual risk of exposure is low. Joe Swartz of McGill University in Montreal stated “you would have to cover yourself in spray” to get to a dangerous level of benzene and that the sunscreen would be “diluted with the same stuff that propels the spray.” There was a handful of sprays found to have no detectable benzene; the brands are listed below.⁸

Mineral Sunscreens

When looking at lotion formulations, it is generally believed that mineral sunscreens have less risk of contamination than chemical sunscreens. Physical sunscreens contain metal oxides such as zinc oxide and titanium dioxide that reflect and scatter UV light. Because of the formulation and size of the zinc oxide compound, it is less likely to be absorbed systemically.¹² Downsides include a “white cast” on skin that makes it a less cosmetically elegant choice. Recently, zinc oxide and titanium dioxide have been broken down and “nanosized” to minimize the white cast.¹²

Because of the small particle size, there is potentially an increased risk of systemic absorption, leading to concerns about their safety. While initial studies suggest that micronized zinc oxide and titanium dioxide do not penetrate deeper layers of the skin,¹² further investigation is warranted to draw a firm conclusion on their long-term effects.

Chemical Sunscreen

Chemical sunscreens include ingredients such as oxybenzone, avobenzone, octisalate, octocrylene, homosalate, ecamsule, and octinoxate. Although studies have shown that these chemicals can be systematically absorbed, no long-term studies have been conducted to show the long-term effects.

Oxybenzone has been shown to be systemically absorbed with higher levels in those who report applying sunscreen.⁵ Oxybenzone has shown to be linked to endocrine disruptions and allergic skin reactions.^6,11 The other active chemicals Homosalate and Octisalate have been undergoing animal studies and have shown similar endocrine disruptor effects.⁶

How did Benzene End Up in Sunscreen?

Benzene is a commonly produced and used chemical that remains an intermediate to many manufactured chemicals.¹⁰ Beyond that, benzene is structurally like many of the common ingredients seen in sunscreen such as avobenzone, oxybenzone, octisalate, octinoxate, homosalate, and octocylene.¹¹

Valisure tested whether benzene was a result of sunscreen actives reacting after product formulation but there was no connection. These results led the company to believe that the benzene contamination was due to contamination in the raw ingredients. These findings illustrate the importance for skin care companies to source quality ingredients.

Another proposed hypothesis is that the contamination happened in manufacturing factories that may be exposed to higher levels of benzene. Although many theories exist, an investigation is ongoing to identify the source of contamination.

Should I Stop Wearing Sunscreen?

Although this study has shown contamination in a handful of products, there are many other sunscreens that had no detectable sunscreen. Manufacturers are constantly working to improve sunscreen products to prevent contamination and this study will encourage companies to test their product to prevent another recall.

Also, it is important to recognize that benzene is found in the air from burning coal and oil, tobacco smoking, gas stations, and vehicle exhaust.¹⁰ The toxic levels in this study are comparable to 24 hours of urban air breathing.⁸ Therefore, it is important to situate the results of the study in the context of everyday exposures to Benzene.

The Skin Cancer Foundation still recommends at least a SPF 30 to protect from risk of skin cancer.⁹ Skin cancer remains the most diagnosed cancer in the world with 9,500 people diagnosed every day.⁹ Sunscreen and protective wear remain first-line in prevention. The choice of sunscreen depends on consumers concerns. Non-nanosized physical sunscreens are a first-line recommendation from dermatologists due to the low systemic absorption of zinc oxide and efficacy in blocking harmful UV rays.

Key Takeaways

1. A recent study by Valisure used gas chromatography on 297 sunscreens and found that 78 tested sunscreens contained a known carcinogen: Benzene.
2. Benzene has been linked with leukemia, is an FDA toxic agent, and the levels should not exceed 2 ppm. The study found a handful of sunscreens that exceeded this limit.
3. In context to daily exposure to Benzene and the risk of skin cancer, sunscreen should still be utilized, and appropriate sun protective methods should continue to be taken.