WASHINGTON -- 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.

Environmental contributors to autism are behind its rising prevalence, U.S. Health Secretary Robert F. Kennedy Jr. said on Wednesday without scientific evidence, adding he plans to look at everything from mold to medicine to identify them.

Kennedy Jr. used newly released autism figures to insist the nation is facing a crisis and promised to ferret out the “environmental toxins” he believes are responsible. The secretary, who in the past has repeated debunked claims that there is a link between vaccines and Autism Spectrum Disorder,