SANTIAGO — Chilean law enforcement officials are investigating the delivery of Iranian crude oil to state energy company ENAP as a possible source of the noxious fumes that caused hundreds of people to seek hospital treatment in August, a prosecutors' office told Reuters.

Police and prosecutors raided ENAP's oil refinery and maritime port in Hualpen and Talcahuano, two adjoining towns 315 miles (505 km) south of Santiago, early on Monday, ENAP confirmed.

Enrique Pena, a spokesman for the Bio Bio region prosecutors' office, said the prosecutor was examining whether there was a link between the company's transfer of Iranian crude oil to its refineries in Hualpen and Quintero, a town 100 miles (160 km) northeast of Santiago, with chemical intoxications in both areas.

A total of 508 people, most of them children, sought medical treatment in Quintero and nearby Puchuncavi in August after residents reported a strong smell in the air, according to Health Ministry figures seen by Reuters.

The environment minister blamed a chemical leak and the environmental watchdog has said ENAP was responsible, something the company has denied.

The Bio Bio prosecutors' office gave no further details about intoxications it said had also taken place in August in Talcahuano.

ENAP is the main oil refiner in Chile, which imports nearly all the fuel it consumes.

The United States reimposed sanctions on Iranian oil exports last month to punish Tehran for its involvement in several Middle Eastern conflicts, but relaxed restrictions for some of Iran’s biggest buyers — China, India, South Korea, Japan, Italy, Greece, Taiwan and Turkey. — Reuters