In his first news conference as secretary of the US Department of Health and Human Services, Robert F. Kennedy Jr. said Wednesday that rising rates of autism prevalence in the US reflect a “preventable” crisis-level epidemic that has been caused by an environmental toxin.

WASHINGTON (AP) — Health secretary Robert F. Kennedy Jr. warned that children in the U.S. are being diagnosed with autism at an “alarming rate,” promising on Wednesday to conduct exhaustive studies to identify any environmental factors that may cause the developmental disorder.

Experts attribute the increase in autism diagnoses to broader definitions and improved detection methods, alongside potential genetic and environmental factors.