Ships are getting bigger. That's making incidents like the Baltimore bridge collapse more complicated.

• Incidents like the Baltimore bridge collapse are "very rare," a marine risk expert told BI.
• But growing vessel sizes in recent decades have made shipping mishaps harder to handle.

Don't jump to conclusions about the dangers of cargo ships after the dramatic destruction of a Baltimore bridge, a marine risk expert says.

The cargo shipping industry is actually getting more safe overall, data shows.

But the sheer size of the vessels in recent decades has made "very rare" mishaps — like the crash that caused the Francis Scott Key Bridge in Baltimore to collapse — more catastrophic and "complicated" to handle, Capt. Rahul Khanna, the global head of marine risk consulting for Allianz, told Business Insider.

A 2023 safety review by Allianz Global found that the number of safety incidents on ships (including collisions and fires) has remained essentially flat year-over-year — to the tune of 3,032 incidents in 2022 and 3,000 in 2021.

But, the data also shows that fewer ships are being lost to the sea.

Incidents of lost vessels have dropped by 65% over the past decade, according to the report, with just 40 ships lost in 2022.

And a 2018 report found there were just 35 major bridge collapses worldwide due to ship collisions between 1960 and 2015 — 18 of which occurred in the United States.

Despite the safety gains, container ships have "grown up in size by as much as 1,500% in the last fifty years," so the vessels now pose more risks to themselves and surrounding infrastructure if a collision does happen, Khanna told BI.

"Back in the '70s" — when the Francis Scott Key Bridge was built — "these container ships … would be less than half the size, or probably even a lot less," Khanna said.

Khanna said that huge ships also mean more complex rescue missions and higher repair costs.

Across the industry, there are ongoing discussions about whether infrastructure and regulation have kept pace with increasing sizes, Khanna said.

It's still too early to say what exactly is to blame for the Baltimore crash. Video of the impact shows the lights turning off and on aboard the shipping vessel.

Authorities later said the crew reported losing propulsion before the crash and called in a "mayday" distress signal. That gave officials enough time to stop traffic to the bridge, most likely saving lives, Maryland's governor said.

Six people remain missing, authorities said Tuesday.

Engineers told BI that the cause of the crash was more likely mechanical failure than mismanagement by the pilot or captain.

Once the vessel hit, the sheer size of the ship — with a gross tonnage of about 95,000 — made the bridge's collapse inevitable.

Khanna — a former captain himself — told BI that "a lot of things have to go wrong together at the same time for something like this to happen."

"This kind of stuff is the worst nightmare of a captain of a ship," he said.

Correction: March 27, 2024 — An earlier version of this story included an unsubstantiated reference to the weight of the cargo ship that struck the Francis Scott Key Bridge. The vessel's gross tonnage is about 95,000; the weight in tons of the ship and its cargo wasn't immediately clear.