Officials declared a public health emergency and warned of the spread of toxic pollutants through the air. The cause of the explosion is not yet clear.
An Iranian with ties to the security services and an international security firm said that a missile fuel component exploded, but Iranian officials did not report any indication of an attack.
President Trump ordered a start to the strikes against the Houthis on March 15. Congressional officials say the campaign has cost well over $1 billion.
