The Trump administration announced earlier this month that hundreds of baby formula samples it tested for toxic chemicals “meet a high safety standard”, but public health advocates warn this claim contradicts data showing a majority were contaminated with dangerous substances, such as Pfas or phthalates.

Independent scientists who reviewed the results say the data gaps and the contamination raise concerns, though they added the testing shows some bright spots, and praised the US Food and Drug Administration for expanding the testing program, then making the results public.

Top FDA officials’ statements also appear to, in part, contradict a 2014 FDA paper that detailed how small amounts of the chemicals found in the current testing likely present a serious risk for newborns who are small, still developing and have a greater food to body weight ratio than adults.

In a statement announcing the results, Department of Health and Human Services secretary, Robert F Kennedy Jr, said: “We tested more infant formula than ever before, and the results are clear: most products meet a high safety standard – but even small exposures matter for newborns.

“We will hold manufacturers accountable, and give parents honest, transparent data they can trust. Protecting our children’s health is non-negotiable,” Kennedy added. The release did not detail the next steps.

Under Kennedy, the FDA launched Operation Stork Speed, which tested 300 baby formula samples for Pfas, phthalates, lead, pesticides, mercury and other dangerous substances that have been found with some regularity in baby formula.

Pfas and phthalates, among the most toxic manmade chemicals, were among the most widespread detections. At least half contained Pfos, one of the most dangerous Pfas compounds for which the federal government previously found no level of exposure in drinking water is safe.

About half of the samples also contained some phthalates, a plasticizer, and some showed relatively low levels of lead. Several samples also had chlorpyrifos, a highly toxic pesticide the EPA tried to ban in 2021. Industry mounted a successful legal challenge to undo the decision.

Maricel Maffini, an independent consultant who does regulatory work aimed at pressuring the FDA to strengthen consumer protections, said she is “encouraged that [the FDA] is moving to test for other things”, but added she was alarmed by the prevalence of endocrine disrupting chemicals, such as phthalates and Pfas.

These especially present a risk because even at low doses they can impact children’s hormones at a key stage of development, causing developmental, reproductive, neurological and other health harms immediately, or later in life.

“There is no really safe amount of endocrine disruptors,” Maffini said. “It seems the overarching argument is that in low amounts they don’t do anything, or are not too risky, but that goes against everything we know about how these chemicals impact the body, and what they can do.”

Significant gaps in the FDA test data also exist – the product names are not listed, so it is unclear which are free from the chemicals. Meanwhile, the agency did not say if a sample contained more than one contaminant. Though little research on exposures to multiple chemicals exists, it is generally thought to have an additive or synergistic effect that makes them even more dangerous.

The FDA wrote that 95% of Pfos levels were below 2.9 parts per trillion (ppt). Drinking water limits are set for four ppt, though those may not be protective of an infant drinking formula, public health advocates say. A wide range of studies have also linked low levels of exposure to Pfas in utero or in infanthood to decreased immunity.

The FDA’s top line of its Pfas results notes that it tested for 30 Pfas compounds, and “most Pfas compounds (25 of 30) were not found in any samples”. But a majority of samples still contained some Pfas, and most at levels that concerned independent experts.

Much of the Pfas were found in dry formulas, which have to be mixed with water that potentially also contains Pfas, and would make the product more toxic, noted Tasha Stoiber, a scientist with the Environmental Working Group non-profit.

“We do know very low levels of exposure are associated with health effects, and … newborns are in this critical stage of development,” Stoiber said. The kind of short-chain Pfas that are used throughout the food system were found in the formulas, Toiber added.

“Thinking about this from a high level – when there is widespread use of Pfas, this is the result,” she said.

The likely source of the phthalates, which were found in 46% of samples, is plastic food packaging or processing equipment. The chemicals give plastic elasticity, but readily shed into food and drinks. Despite the risks, the FDA has not set any enforceable limit on phthalates, established a safe level of daily intake, and has put in place few other guidelines around it.

Marty Makary, the FDA commissioner, called the results “encouraging”.

“You can judge a society by how it treats its most vulnerable members,” Makary said. “That’s why we’re doing everything in our power to make sure our babies and infants have safe, high quality formula options that are backed by a resilient supply chain.”

Lead and other metal contamination has long been a problem in baby formulas, and the levels in the most recent tests are comparatively lower than they have been in the past, said Tom Neltner, director of the Unleaded Kids non-profit. That indicates public and political pressure on industry to act is working, he said, but added that the FDA’s snapshot of formulas is not enough to ensure safety.

“We need ongoing transparency,” Neltner said.

Industry regularly tests its formulas, but the FDA claims it largely does not have the authority to view them, which Neltner said is untrue. New legislation introduced in California and Vermont would require formula producers to share their test results with the public. Neltner praised the administration’s expanded testing, and said the FDA’s next step is to set an action level on lead, which does not yet exist.

“The next step can’t be to declare it safe, because there is no assurance that companies will keep it at these levels,” Neltner said.