A tractor trailer load of pennies spilled early Thursday morning onto northbound Interstate 95 in Delaware, causing traffic delays.

The incident happened around 2 a.m. on the highway near the Interstate 295 split, according to Delaware State Police. The truck overturned. It was not immediately known what caused the truck to flip. The crash is under investigation.

The driver of the truck suffered minor injuries.

Many lanes of the highway were closed as crews dealt with the cleanup. Several local news outlets said area officials described the roadway as being slippery because some fuel may have also spilled. The pennies, according to local TV station Fox 29 in Philadelphia, were being sent to a division of the U.S. Mint in Philadelphia to be stamped.