The boom on a 15-ton excavator struck the US-12 bridge in Niles Charter Township Thursday morning, prompting an inspection of the bridge and causing major headaches for drivers.

The Caterpillar 312cL excavator was from Michigan Rental of Niles. It was being hauled north on South 11th Street on a flat bed semi when around 9:30 a.m. the boom struck the US-12 eastbound bridge, which has a clearance of 13 feet, 9 inches.

The excavator became wedged between the bottom of the bridge and the flat bed, but somehow did not fall off the flat bed.

Emergency crews quickly shut down South 11th Street — also known as M-51 — near the bridge and a portion of eastbound US-12 that goes over the bridge. Both roads were re-opened by 3 p.m., around 5 1/2 hours later.

The impact of accident caused some damage to girders on the bridge, prompting an inspection by officials from the Michigan Department of Transportation.

Bridge debris could be seen scattered on South 11th Street around the semi. The accident also caused the excavator to leak fuel, prompting clean up by Niles Township and Niles City firefighters before the fuel could reach nearby storm drains.

Lt. Trent Babcock, of the Berrien County Sheriff’s Department, said an initial inspection of the bridge by MDOT officials found that the bridge was safe to drive on and under.

However, Babcock said an MDOT structural engineer would take a look at the bridge within 48 hours to determine how to fix the damage.

Until that is done, the shoulder of eastbound US-12 on the bridge will remain coned off. Both lanes are open.

Officer Jerry McClearen, of the Michigan State Police Niles Post, said an investigation found the driver was at fault for the incident.

When asked if the driver had received a citation, McClearen said they don’t typically release that information.

The driver was going the speed limit — 50 miles per hour — when excavator hit the bridge, McClearen said.