KITTERY — The Sarah Mildred Long Bridge, connecting Maine and New Hampshire, will be closed for several days because of an accident Monday in which a 470-foot tanker drifted from its moorings and hit the bridge.

The accident Monday afternoon on the Piscataqua River damaged bridge supports and left a 20-foot dent in the ship’s side. The Coast Guard said there was no puncture to the ship and no fuel spilled into the water. The tanker was carrying tall oil – or tallow – made from wood pulp, and yellow grease, said Lt. Nick Barrow, a Coast Guard spokesman.

“We were ready for the worst case and had teams ready, but thankfully we didn’t need that,” Barrow said.

The tanker got pinned against the bridge with the rising tide of the tidal river, the Associated Press reported. Tugboats moved the vessel away from the bridge Monday evening between high and low tides, when currents were minimal.

The bridge will be closed for several days, said N.H. Department of Transportation Commissioner Chris Clement.

It will remain closed into Tuesday and possibly longer so crews can inspect the structural damage and determine what repairs are necessary, Bill Boynton, another spokesman for the department.

Clement said the bridge sustained damage to both vertical supports. Chunks of granite from the supports fell off and ended up on the deck of the ship.

“That’s granite, real New Hampshire granite, that broke,” Clement said. “There was broken granite on the ship’s deck when it came in.”

Clement said the ship’s owners will be responsible for the cost of repairing the damage. He declined to estimate the cost.

The bridge is owned by Maine and New Hampshire.

The ship was being refueled when it began to move from the New Hampshire State Pier in Portsmouth, N.H., snapped its mooring lines and drifted for five minutes before hitting the bridge.

“Nothing at the facility failed,” said Port Director Geno Marconi. “I can’t say whose fault it was.”

The ship started to drift around 1:30 p.m. It was eventually tugged back to the dock around 6 p.m.

Pepperell Cove Marine, the company that’s responsible for tying up the ships, could not be reached for comment Monday.

Marconi said a scrap metal and road salt facility closed for the day because of the marine traffic disruption.

The Sarah Mildred Long Bridge, which is not open to pedestrians or cyclists, carries about 14,000 vehicles per day.

With the bridge closed because of the collision, the Interstate 95 bridge is the only route across the Piscataqua River between Kittery and Portsmouth, N.H.

Nearby, a new Memorial Bridge is under construction.

While the Sarah Mildred Long Bridge is closed to vehicular and marine traffic, small boats can traverse the river through another opening in the bridge.

The 73-year-old bridge, which carries traffic along the Route 1 Bypass, is scheduled for demolition in 2015.

In January, its center span got stuck open during a routine test when an electrical malfunction prompted one of the lift motors to keep running.

According to Marinetraffic.com, the ship, the Harbour Feature, was built in 2011 to carry oil and chemicals. Its last port of call was Savannah, Ga.

The ship sails under the Portuguese flag. The shipping agent is listed as Nordic Tankers, based in Denmark. A person who answered the phone at Nordic Tankers’ office in Stamford, Conn., said “no comment” when asked about the ship.

The Coast Guard said the 20-foot dent was visible on the ship’s port side, and there may be damage to the vessel’s bridge.

Dive teams will inspect the ship underwater. The timing of that will depend on weather and tides.

“The inspection phase begins immediately and will go straight into an investigation phase to determine what happened and how to prevent it from happening again,” Barrow said.

It would be unusual for the Coast Guard to charge anyone for the cost of inspections, he said.

U.S. Rep. Chellie Pingree, D-Maine, said there was no direct environmental threat.

“Obviously a significant spill of any substance could cause environmental problems, but at least this vessel wasn’t carrying a large amount of a petroleum product,” she said.

Pingree said the ship’s crew will get alcohol and drug testing.

Pingree is married to S. Donald Sussman, majority share owner of the Portland Press Herald.

The Coast Guard will lead the investigation and determine when the ship may be able to sail again. “It could be a long process,” Barrow said.

About 50 to 75 people, including staff from the Coast Guard and the N.H. Department of Transportation, were involved in the response.

One onlooker, Kristy Nichols of Eliot, said she worried about the coming tourist traffic in the warmer months.

“We’ve already got one bridge down and now we’ve got this problem,” Nichols said. “It could be rough going into the summer season.”

– Staff Writer Matt Byrne contributed to this report.

Jessica Hall may be reached at 791-6316 or at:

jhall@pressherald.com