WASHINGTON, Sept. 7 (UPI) -- Less than a week after the U.S. Food and Drug Administration announced a ban on 19 chemicals used in antibacterial soaps because they may pose a risk to rising resistance of bacteria to antibiotics, a new studies suggests one of the chemicals is found in indoor dust and contributes to the problem.
The chemicals triclosan and triclocarbon, as well as four other antimicrobial chemicals, were found in house dust by researchers at the University of Oregon, Harvard University and Arizona State University, according a study published in the journal Environmental Science and Technology, suggesting their use in cleaners is contributing to antibiotic resistance.
Researchers in the study analyzed dust samples from an indoor athletic and educational facility, detecting triclocan, triclocarban, and methyl-, ethyl-, propyl- and butylparaben in the dust samples. The researchers then studied dust microbes, finding antibiotic resistance genes, which can be passed between bacteria, linked specifically to the six cleaning chemicals detected in the initial analysis.
Samples with higher amounts of triclosan, beyond other chemicals, also had higher levels of genes linked to bacteria resistant to multiple drugs -- which they say is contributing to the antibiotic resistance.
The FDA issued a rule on September 2 requiring manufacturers to remove 19 chemicals from antibacterial soaps, but not hand sanitizers or antiseptics used in healthcare and food handler settings, because of potential health risks.
Among the now-banned chemicals, triclosan is the most widely used. The chemical was widely used primarily by surgeons to sterilize their hands; however, triclosan started to be added to consumer chemicals, soaps, deodorants and laundry detergents in the mid-1990s.
Triclosan also was not required by the agency to be removed from toothpaste, baffling some researchers. After ruling in 1997 that the chemical's use was not only safe, but also appeared to be more effective at cleaning teeth and preventing gum disease than products not containing it, the agency did not include it among products that need to be reformulated.
"We put soap on our hands, and a small amount gets into our body," Rolf Halden, a director for environmental security at the Biodesign Institute at Arizona State University who was among researchers involved with the house dust study, told the New York Times, adding that "[through the gums] chemicals get rapidly absorbed into the bloodstream."
The FDA ban referred to safety concerns, but said the ban was motivated by the failure of manufacturers to show that their presence in products either made antibacterial soaps more effective or proved their safety. This caveat -- that the agency did not call the chemicals unsafe -- has been pointed out by some manufacturers.
"Consumer antibacterial soaps and washes continue to be safe and effective products for millions of people every single day," industry representatives at the American Cleaning Institute said in a press release. "Antibacterial soaps are critical to public health because of the importance hand hygiene plays in the prevention of infection. Washing the hands with an antiseptic soap can help reduce the risk of infection beyond that provided by washing with non-antibacterial soap and water."