KENNER, La. (AP) — Fumes from a mysterious substance wafting from a tractor trailer truck sent 17 Louisiana State Police troopers, Jefferson Parish Sheriff’s deputies and DEA agents to the hospital Friday. A police dog also had to be taken for medical care.

DEA Public Information Officer Roberto Bryan Jr. said a traffic stop exposed officers to a substance that made them sick.

‘‘There was cocaine and also pesticides in the truck,’’ Bryan said. ‘‘It is believed the pesticide is what made the officers sick.’’

‘‘The investigation is still going on to determine what the pesticide is,’’ he added.

The officers were taken to East Jefferson General Hospital and quarantined as a precaution. They were released by mid-afternoon, Bryan said.

The long-term effects of the pesticide on the officers was not yet known, Bryan said. They were well enough to return home, however.

Hospital spokesman Keith Darcy said the emergency room was shut down for several hours while they dealt with the contamination. A decontamination unit was set up in the hospital’s parking lot next to the emergency room and the officers went through it, Darcy said.

The incident began when a state police trooper spotted an 18-wheeler he was suspicious of on Interstate 10 in St. John the Baptist Parish west of New Orleans, said Lt. Doug Cain, a state police spokesman.

‘‘The officer became suspicious the trucker might be hauling narcotics,’’ Cain said. ‘‘He was given consent to search the truck and saw a white powder in it.’’

The trooper secured the truck and called in members of the High Intensity Drug Trafficking Team, which is made up of Jefferson Parish sheriff’s deputies, DEA agents and state troopers, Cain said.

The truck was moved to state police headquarters in Kenner to be searched, Cain said. During that search, several more containers of white powder — in kilogram-size bricks, were found amid a cargo of limes, he said. Authorities say that is a common way for cocaine to be packaged.

The search eventually revealed 23 kilos — more than 48 pounds — of cocaine in the truck with an estimated worth of about $500,000, Cain said.

‘‘As the search went on the officers became overcome with nausea and dizziness,’’ Cain said.

As a precaution, the officers who drove those to the hospital were also decontaminated, he said, adding, ‘‘The truck has been secured and the substance is not a threat to the public.’’

Members of the state police hazardous materials team and fire departments inspected the truck’s contents to determine what caused the officers’ symptoms.

The driver of the truck, David Aparicio, 47, of Sinton, Texas, and his brother Francisco Aparicio, 45, of Taft, Texas were booked in St. John Parish on possession of cocaine with intent to distribute, authorities said.

The truck had CG Transport on the sides, Cain said, adding it hadn’t yet been determined if that was a legitimate company.