The Environmental Protection Agency allowed a pesticide known as nanosilver to be used in textiles, meaning it could appear in bedsheets, clothing and other fabrics without the knowledge of consumers.

Nanosilver, a microscopic form of silver, is used as an antibacterial agent and serves as a preservative for textiles. While initial tests have not shown that it is toxic to humans, data on its long-term effects is lacking.

The EPA granted Swiss company HeiQ a conditional registration for its nanosilver product in 2011, allowing it onto the market while further toxicity studies were conducted.

“In granting a conditional registration for nanosilver in textiles, the EPA acknowledged that people will be in direct contact with nanosilver from these textiles, including workers who make the clothing, consumers who use and wear it, and infants and babies who lay against it and suck or chew their parents’ treated clothing,” a recent report from the National Resources Defense Council reads.

The NRDC said in its report that lab tests have shown that nanosilver can travel through the bloodstream and enter into the cells of vital organs such as the brain and lungs, potentially causing long-term damage.

The EPA gave HeiQ a four-year period to gather more data on the health effects of nanosilver, but it has yet to produce information on how it affects human development and reproductive systems, the potential dangers of inhalation during production and its toxicity through skin contact.

“These kinds of studies should be done before [nanosilver] goes to the market,” Jennifer Sass, toxicology and environmental health scientist at the NRDC, said in a phone interview with the International Business Times.

Additionally, nanosilver is known to be harmful to beneficial microorganisms such as algae and daphnia, which are important for the environmental health of many ocean and river ecosystems.

With increased production and distribution of nanosilver, the NRDC says the pesticides may be contaminating water supplies and damaging aquatic ecosystems but that such data has yet to be obtained, while use of nanosilver expands.

The Silver Nanotechnology Working Group, a consortium of businesses that produce nanosilver, argues that nanosilver has been safely applied safely for decades.

“Environmentalist organizations have perceived nanotechnology to be a new technology that is opportunistic to campaign against,” the SNWG said in a statement. “Nanosilver has been selected as a key target for nano-fear campaigning.”

Sass said that nanosilver producers have based their arguments on toxicity studies of conventional silver, but that nanosilver acts on different principles due to its microscopic size and further studies must be conducted.