WEST YELLOWSTONE, Mont. (AP) — A tanker truck hauling gasoline in Yellowstone National Park rolled over Friday and spilled an estimated 4,800 gallons (18,200 liters), officials said.

An investigation was underway to determine whether any of the unleaded gas entered an area creek.

The truck’s driver lost control of the rig during the early morning accident along Highway 191, which runs through the western side of the park near the Montana-Wyoming border, park officials said in a statement.

No injuries were reported and it was not immediately known if any fuel entered Grayling Creek, a small waterway that flows from the Gallatin Mountains and drains into Montana’s Hebgen Lake.

One lane of the highway was closed Friday evening as cleanup efforts were underway.