The FDA's action follows the July publication of a small pilot study that found arsenic and lead in organic and non-organic tampons. Although the levels of both metals were low, there is no safe level of exposure to lead, according to the US Environmental Protection Agency.
The July study discovered only the presence of the metals and "did not test whether metals are released from tampons when used," the FDA said in a statement Tuesday. "It also did not test for metals being released, absorbed into the vaginal lining, and getting into the bloodstream during tampon use. The FDA has therefore commissioned an independent literature review and initiated an internal bench laboratory study to evaluate metals in tampons."
The FDA lab study will mimic normal use of tampons to see just how much - if any - metals may be released into the human body during their use. The literature review will examine all research in the area to shed light on the potential health impact of such exposure, the agency said.
"We want the public to know that before tampons can be legally sold in the U.S., they must meet FDA requirements for safety and effectiveness," the statement says. "Manufacturers must test the product and its component materials before, during, and after manufacturing.
"Before a product is allowed onto the market, biocompatibility testing is undertaken by the manufacturing company, which is part of safety testing, and is reviewed by the FDA prior to market authorization."
The Consumer Healthcare Product Association, a trade group, also noted in a statement that its products "are rigorously tested" to meet "strict regulatory standards." The group said it "is supportive of continued research to help ensure the safe use of these products."
The Center for Baby and Adult Hygiene Products, a trade association also known as BAHP, said it supports the FDA's further research on the safety of tampons in real world use and the agency's ongoing commitment to public health.
Heavy metals in tampons
The July study tested 30 tampons from 14 brands purchased from major online retailers and stores in the United States, the United Kingdom and Greece. The researchers conducted a blinded study, so they did not know the brands.
Researchers ran tests for 16 heavy metals: arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, manganese, mercury, nickel, lead, selenium, strontium, vanadium and zinc, according to senior study author Kathrin Schilling, assistant professor of environmental health sciences at Columbia University's Mailman School of Public Health in New York City.
"We found an average of 100 nanograms per gram of lead and 2 nanograms per gram of arsenic in the tampons," Schilling told CNN at the time. "There was no detectable level of chromium and no detectable level of mercury, which is very good."
Organic tampons contained higher levels of arsenic, while nonorganic tampons had higher levels of lead, the study found.
"The average lead concentration in tampons was about 10 times higher than the maximum levels currently allowed in drinking water," Schilling said, adding that arsenic levels were five times lower than current limits for drinking water.
"It's important to note that arsenic shouldn't be present in tampons at all, and we don't yet understand the effects of vaginal exposure since it hasn't been studied," she said. "There is no safe level of lead exposure, and it has been shown to cause reproductive health issues in women."
However, the mere presence of a chemical is not an indication of risk or adverse effect, according to the American Chemistry Council, an industry association.
"As the Centers for Disease Control and Prevention emphasizes, 'The measurement of an environmental chemical in a person's blood or urine is a measure of exposure; it does not by itself mean that the chemical causes disease or an adverse effect,'" a spokesperson for the council previously told CNN.
Why tampons would be more of a concern
Vaginal tissue is more permeable than other parts of the body, so if studies were to find that heavy metals - or worrisome chemicals - do leach from menstrual products into the body, it could be a significant problem, Anna Pollack, associate professor of global and community health at George Mason University in Fairfax, Virginia, told CNN previously. She was not involved in the pilot study.
"I am most concerned with menstrual products that are used inside the body," said Pollack, who coauthored a review of 10 years of studies on contaminants in tampons, sanitary pads, menstrual cups and other products.
"However, there is no reason for people to be afraid to use menstrual products at this time," Pollack added. "I would just be aware of the issue and monitor any research that develops."
Tampon makers and the FDA recommend that tampons not be used at night or for longer than eight hours due to a greater risk of toxic shock syndrome, a deadly bacterial infection that can cause organ failure and death if not treated.
That advice also applies to anyone concerned about heavy metals or chemicals in their menstrual products, experts say.
Other recommendations include washing your hands before and after inserting or removing a tampon to reduce bacterial spread, changing tampons every four to eight hours and using the lowest absorbency possible.
"If you can wear one tampon up to eight hours without changing it, the absorbency may be too high," the FDA noted on its website.
Signs of toxic shock, which include a sudden high fever, diarrhea, dizziness, vomiting or a rash that looks like a sunburn, need immediate medical attention.
In addition, "if you have discomfort, pain or other unexpected symptoms like unusual discharge when trying to insert or wear a tampon, or if you have an allergic reaction, stop using tampons and contact your provider," the FDA said.
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