Authorities in Washington, D.C. are investigating the cause of a pedestrian bridge collapse that sent four people to the hospital on Wednesday.

The bridge collapse at I-295 near Polk Street NE. was reported by D.C. Fire and EMS shortly after 11 a.m. on June 23.

Six people were evaluated for injuries and four were transported to a hospital for treatment.

A Hazmat unit responded to the bridge collapse after diesel fuel spilled from a truck that was partially wedged under the collapsed structure.

Authorities have not provided information on what caused the bridge to collapse at this time.