The majority of Americans rely on sunscreen to protect their skin from ultraviolet radiation during sun exposure, especially during the summer months. In light of recent media coverage on low levels of benzene detected in several sunscreen products, we examined dermal exposure to benzene from topically applied consumer products.

Valisure is a US-based online pharmacy that routinely tests consumer products. Earlier this year, Valisure reported benzene contamination in sunscreens and after sun care products. Benzene is ubiquitous in the atmosphere. It is formed from natural processes, such as forest fires and volcanoes, and has many common sources, such as cigarette smoke, gas stations, motor vehicle exhaust, industrial emissions and from products containing benzene such as glues, paints and furniture waxes.¹ Also, benzene is a known human carcinogen and is associated with nervous system effects; dermal exposure to benzene may cause irritation and redness. 

However, benzene is not expected to be found in topical skin care products or over-the-counter (OTC) drugs. Because sunscreen contains active ingredients used in the prevention of skin cancer, sunscreen is classified as an OTC drug by the US Food and Drug Administration (FDA).

Valisure tested 294 sunscreen product batches from 69 different brands through gas chromatography. They found low part-per-million (ppm) concentrations of benzene in 78 of the products tested. Of the 78 product batches with detectable benzene, nearly 49% had concentrations below 0.1 ppm (38 product batches), 33% had concentrations between 0.1 and 2 ppm (26 product batches) and 18% had concentrations between 2.78 and 6.26 ppm (14 product batches). The large majority of product batches with detectable benzene concentrations were spray sunscreen formulations and after sun products.


Sprays & Gels

The trace benzene contamination was not specific to a particular brand or product. Brands with product batches that had detected levels of benzene over 2 ppm also had product batches with no detected benzene. Further, when multiple batches were tested within one product type (such as alcohol sprays), benzene concentrations were not consistent. However, 90% of the product batches with benzene detections were alcohol-spray or gel formulations.  The discovery of trace benzene contamination led to the voluntary recall of at least one company’s aerosol sunscreen products.^2,3,4 However, the company emphasized that other sunscreen product forms (lotions, sticks, and face mist sunscreens) were not impacted by the voluntary recall. 

Coincidentally, the manufacture of these alcohol-spray sunscreen formulations occurred during the period when FDA permitted the use of fuel grade alcohol in hand sanitizer products during the COVID-19 public health emergency.⁵ Benzene is not added to sunscreens or other topical OTC drugs during formulation nor is it a result of the degradation of an intended ingredient. Rather, benzene is a trace contaminant that may be introduced to a formulation during manufacturing. Given that the primarily affected batches were alcohol-spray formulations, it could be that fuel grade alcohol made its way into the supply chain for spray sunscreen products.

Currently, the concentration of benzene is limited to 2 ppm in alcohol-based hand sanitizers⁶ and/or drugs with significant therapeutic benefits. Because the intentional introduction of benzene into drugs or consumer products is not permitted, benzene’s presence in therapeutic products is presumably due to inadvertent introduction during production. However, the FDA limits for impurities in fuel grade alcohol also includes methanol, acetaldehyde, acetal (1,1-diethoxyethane), acetone, ethyl acetate and several other alcohols.

While benzene is classified as a human carcinogen, the health risk of benzene exposure depends on the concentration of benzene that an individual is exposed to, the route of exposure, frequency of exposure and duration of exposure.  Further, regarding dermal exposures to benzene, additional factors need to be considered. For example, recreational sunscreens may be applied to the entire body but relatively infrequently—perhaps one to four times per day. On the other hand (no pun intended), hand sanitizer is only applied to the hands and possibly the forearms, but it may be applied relatively frequently, particularly in a healthcare setting where one might anticipate over 100 applications during a typical work shift.  There are other factors that may affect dermal absorption of a product at one location of application versus another, including skin integrity, the thickness of the skin at the location of application, the water content of the skin at the location of application, and skin temperature and the concentration of the chemical on the skin surface. For any product where an undesirable impurity is present, a formal risk assessment should be conducted to understand the risks and take action if necessary.

Moreover, given the numerous disruptions in supply chains as a result of the COVID-19 pandemic, consumer product manufacturers need to be vigilant with the raw materials they are receiving. For alcohol in particular (both ethanol and isopropyl alcohol), raw materials should be screened for benzene and other potential impurities to assure that products are not unintentionally adulterated.  Beyond the regulatory liabilities, there are legal liabilities associated with these impurities.  For example, several 60-Day Notices under California Proposition 65 have been filed with the Attorney General for benzene in sunscreen, and dozens more for benzene and acetaldehyde in hand sanitizer in July and August 2021 alone. Most recently, in September, Coppertone issued a voluntary recall of several sunscreen sprays due to the presence of benzene. However, the greatest risk may be to the brand, for which safety, purity and healthiness are often front of mind for today’s consumers. 


About the Authors
Paul DeLeo, PhD, is a principal at Solleone Consulting, Inc.

Christina Ross, MPH, is a project scientist at Integral Consulting. More info: Christina Ross, email: [email protected]

References:

1. https://emergency.cdc.gov/agent/benzene/basics/facts.asp
2. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/johnson-johnson-consumer-inc-issues-voluntary-recall-specific-neutrogenar-and-aveenor-aerosol
3. https://www.neutrogena.com/sunscreen-recall.html
4. https://www.aveeno.com/sunscreen-recall
5. https://www.fda.gov
6. https://www.cdc.gov/niosh/topics/skin/default.html