More than 600 U.S. veterans of the Iraq War said they were exposed to chemical weapons agents since 2003 and that the Pentagon took little or no action, The New York Times reported Thursday.
Thursday's report said Defense Secretary Chuck Hagel discovered the incidents of exposure during an internal review of questionnaires that troops filled out at the end of their deployments in Iraq.
A total of 629 service personnel reported exposure to degrading chemical agents in Iraq, including mustard gas agents.
The Times reported that others also may have been exposed, including foreign soldiers, contractors and Iraqi troops and civilians.
The newspaper said Pentagon officials failed to recognize the large number of reported cases or track affected soldiers to offer adequate medical treatment. It is unclear why the Pentagon failed to act, but defense officials said they will now reach out to veterans who report encounters with chemical agents.