At approximately 05:20 hours units were alerted to a tractor trailer accident on Interstate 95 Southbound at the 133 mile marker bringing Rescue 1 with three Volunteers. Units arrived on the scene to find a box truck that had rear ended a tractor trailer damaging the tractor trailer's cargo which was found to be very hazardous. Upon discovering this Command upgraded the incident to a HazMat bringing the Fredericksburg and the Northern Virginia Regional HazMat Teams as well as the Virginia Department of Emergency Management. Units backed to a safe distance and secured the area while awaiting the Regional HazMat Teams response. Once on scene the Fredericksburg Regional HazMat Team assisted by the Northern Virginia Regional HazMat Team investigated and mitigated the incident. Rescue 1 assisted with the Decontamination of the HazMat Teams before returning to service approximately 6.5 hours later.