AMSTERDAM, Netherlands ?  Three tons of hashish went up in smoke Friday, incinerated by Dutch authorities after a van carrying the illicit cargo crashed and scattered it across the road.

Detectives were hunting the van's driver and a passenger who fled the scene, leaving behind the wrecked vehicle and its $20 million cargo.

"It's not something you see every day," police spokesman Hielke Vogelzang said, adding that police were tracing the owner of the van, but "it may be stolen or leased."

The crash happened during the morning commute on a highway outside the town of Avenhorn, about 20 miles north of Amsterdam, police said.

Vogelzang said it was unknown whether the vehicle's occupants were injured, but "we're confident we'll catch up to them sooner or later."

Police said the van was heading toward Amsterdam when its driver lost control for unknown reasons. They said eyewitnesses saw the van hit a barrier, flip and clip another car before coming to rest. The two occupants ran away.

Packages of hash were scattered around the area, local media reported, and Vogelzang said that hundreds more were found stacked on wooden pallets inside the van.

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Marijuana and hash are technically illegal in the Netherlands, but under the country's tolerance policy, police do not arrest anybody for possession of small amounts.

It is sold openly in licensed shops — which, paradoxically, have no way of legally acquiring their chief product.