In its critique of the 2004 study, a Merck KAag toxicologist cited results of two studies performed in Merck KAag's own laboratories that concluded DHA was safe for consumers. Those Merck KAag studies were never peer reviewed and are not available to scientists or the public for review. When ABC News asked for a copy, Merck KAag declined to provide them.
ABC News also asked the European Commission for a copy of the papers upon which it based its 2010 opinion. The commission responded that it generally doesn't release copies of such papers and that permission would have to be granted from the entity that asked for a review.
In America, the FDA said that no manufacturer has ever attempted to present similar evidence or go through an American safety review of DHA in spray tans.
The agency told ABC News in an email that it does not step in to stop what it calls on its website "the unapproved use" of DHA because, "FDA does not regulate the operation of commercial enterprises such as indoor or sunless tanning salons. This would be a function for OSHA or state/local public health regulators, much as for hair or nail salons. FDA has oversight responsibility for the safety of the cosmetic products and the devices [UVA light sources and beds] in the indoor tanning salons."
ABC News checked with local regulators in New York City and confirmed that no city agency regulates spray tan applications. The New York Department of Health, which regulates UV tanning, does not regulate spray tans.
Industry groups such as the International Smart Tan Network were unaware, when asked, if any state or local entity anywhere regulates spray tans.
Swift Response From a Major Tanning Salon Chain
Two of the 12 salons ABC News visited in its random undercover check belonged to the company Beach Bum Tanning, whose top trainer, Dante Fitzpatrick, said DHA was "super safe" and "great for pregnant women."
ABC News went back to Fitzpatrick and openly asked him if he believed DHA was safe to drink. He responded by taking a vial of the DHA fluid and drinking it.
Subsequently, the CEO of Beach Bum Tanning, James Oliver, contacted ABC News to say his company was taking swift and widespread steps to make sure consumers were educated about the FDA's recommendations and take all necessary safety precautions.
In response to this report, Oliver said he has now posted a sign in all of his stores informing customers of the FDA's recommendations. Beach Bum is also making a version of the sign available to hang on the walls in all sunless booth and airbrush rooms, recommending the use of protective gear while spray tanning.
A spokesman for a Washington, D.C.-based public relations firm told ABC News it also prepared an email that was to be sent out to Beach Bum's entire customer base saying the same.
In addition, Beach Bum has since posted the recommendations on its Facebook page, where it estimates 9,000 people may have seen it.
"We, at Beach Bum Tanning, are always striving to promote both customer and employee safety in the use of both UV and spray tanning equipment," Oliver wrote in a statement. "As products and research evolve, it sometimes becomes necessary to revise and update our policies and customer standards. Although we have always made eyewear, nose guards and lip balm available to every sunless booth and airbrush tanning customer, effective immediately we are taking the following steps to better inform our customers on the FDA guidelines:
"We have already started ...
" making available a copy of FDA Guidelines to all customers using sunless equipment
" posting signs in every room stating 'As per FDA guidelines, we recommend the use of protective eyewear, nose plugs and lip balm during every sunless tanning session.'
" updating our website to include the FDA recommendations on all pertinent pages: Sunless Booth page, Airbrush tanning page and Airbrush FAQ's;
" retraining our staff to more actively recommend the protective gear.
"We know that our actions go above and beyond the FDA recommendations," Oliver wrote, "but we feel, in light of the unknown effects of the DHA mist, it is in everyone's best interest to take these proactive steps."
Oliver later told ABC News he is also purchasing new top-of-the-line industrial fans for his salons that will remove as much of the DHA from the air as soon as possible after application. He said that was intended to provide the safest possible experience for consumers who wish to continue to spray tan.
He said that would make using salons such as his safer than using at-home products that can be purchased over the counter and applied by consumers in a closed-in shower.
ABC News' Teri Whitcraft and Mollie Riegger, and former medical residents Murtaza Akhter and Rishi Sharma, contributed to this report.
Our panel of six experts included Dr. Arthur Grollman of Stony Brook University, Dr. Lynn Goldman of George Washington University, Dr. Rey Panettieri of the Univ. of Pennsylvania Perelman School of Medicine, dr. Fred Guengerich of Vanderbilt University, and Dr. Darrel Rigel of NYU.