Vehicles and a pedestrian cross the Casco Bay Bridge in Portland on Friday. Derek Davis/Staff Photographer

Engineers have said no bridge could withstand a strike against one of two major supports, like the blow by a container ship that took down the Francis Scott Key Bridge in Baltimore last week. 

But the collapse, which is believed to have killed six construction workers, has prompted some to wonder whether a similar disaster could happen in Portland.

It already has happened – on a lesser scale – but it’s rare for ships traveling in or out of Maine’s largest port to even brush up against the Casco Bay Bridge, according to the harbor master.

The drawbridge that connects downtown Portland and the Knightville neighborhood of South Portland is the only one that cargo ships travel under when navigating into or out of the Port of Portland.

But there are three large differences between the Casco Bay and Francis Scott Key bridges: Much smaller boats come into the Portland Harbor, the bridge has safety protections required for newer structures that the older Baltimore bridge wasn’t required to have, and the harbor has tugboat assists that help ships move through the harbor.

“While nothing is indestructible, I am 100% confident that I can drive over that bridge with my family and not give a second thought to its safety,” Maine Department of Transportation spokesperson Paul Merrill said.


Four energy companies have terminals past the Casco Bay Bridge, in the Fore River. The Maine Port Authority’s International Marine Terminal – the sole docking area for container ships – sits near the base of the bridge.

In 1996, a tanker carrying 200,000 barrels of heating oil crashed into the side of the Casco Bay Bridge’s precursor, the Million Dollar Bridge. The bridge ripped a 30-foot hole into the hull of the ship, pouring nearly 180,000 gallons of oil into the Fore River.

No one died, and the bridge was only mildly damaged, then replaced the next year.

Portland Harbor Master Kevin Battle said he’s seen four vessels strike the Casco Bay Bridge since he started working at the agency in 2004. But all were minor “sideswipes” or “glancing blows” caused by “Mother Nature,” meaning strong currents and wind gusts, Battle said.

And none came close to bringing the bridge down thanks to its protectors, the fenders, which are wooden and steel layers that safeguard the structural integrity of the bridge.

The Maryland Department of Transportation has not yet confirmed what safety measures were incorporated into the Key Bridge’s design, including fenders to protect the struck pier that was the first to buckle.


Maine officials have rated the condition of the Casco Bay Bridge, which opened in 1997, at a seven out of nine, according to its last biannual inspection in January 2023. That’s one point higher than the rating the Key Bridge had.

“It’s pretty darn good, and we don’t need to worry about it in the whole scale of things,” Maine Department of Transportation Bridge Maintenance Engineer Ben Roberts said. “There’s no structural issues at all.”

There are “some minor problems” noted in the inspection report, which Roberts chalked up to peeling paint and minor cracking on the wearing surface, which cars drive over.

About 13,300 vehicles travel on the four-lane bridge daily, according to the inspection report.

“A seven is very appropriate for the age of this bridge. We would expect it to start to see some things but not to see anything that would be concerning enough that we would go out and do some kind of rehabilitation project,” said Joyce Noel Taylor, MDOT’s chief engineer. “I don’t worry about that bridge collapsing over.”

The National Transportation Safety Board, which investigates aviation, railroad, highway, marine and hazardous-materials accidents, has documented just two boating incidents in Portland Harbor since 2010, the earliest year for which there are online records. Neither involved cargo ships: one was a fishing vessel that sunk in 2018, and the other was a cruise ship that was damaged by a fiery explosion in October.

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