Health officials say chemicals found in everything from pizza boxes and microwave popcorn bags to carpet treatments and cosmetics may not be safe for humans or the environment. The chemicals, known as poly- and perfluoroalkyl substances, or PFASs, are used in products to improve their durability and increase their shelf life, but may be linked to potential health issues like kidney cancer and thyroid disease.

An international team of scientists are calling for manufacturers to stop using the chemicals while safer alternatives are explored. The warning came in the form of a National Institutes of Health study published Friday in the journal Environmental Health Perspectives.

"The question is, should these chemicals continue to be used in consumer products in the meantime, given their persistence in the environment?” the authors wrote. “And, in the absence of indisputably safe alternatives, are consumers willing to give up certain product functionalities, such as stain resistance, to protect themselves against potential health risks?" Scientists said the chemical industry should phase out PFASs and that countries should restrict their use through tighter regulations.

PFASs are used in thousands of products worldwide, including water-repellant and stain-repellant clothing, certain cosmetics, camping tents and nonstick pots and pans. Manufacturers of PFASs insist the chemicals are safe.

However, scientists say there isn’t enough research to back up such reassurances. Previous studies carried out between 2005 and 2013 have shown that PFASs stayed in people’s bodies for years and may increase the risks of certain cancers. In light of those studies, manufacturers began replacing their PFASs with slightly different versions of the chemical that they said were not as toxic.

"The concern really is that we are replacing old chemicals with new chemicals that have similar structures," Bill Walker, a consultant with the Environmental Working Group, based in Washington, and co-author of a separate study into the potentially dangerous side effects of PFASs, told NBC News. "We don't want to repeat history again here."