When the Francis Scott Key Bridge collapsed in the early hours of March 26, former Gov. Parris Glendening thought back to two studies from more than 20 years prior that suggested potential protections for the span but were never acted on by government officials.

He didn’t remember the reports in detail — one of which came out during the final months of his administration, and another which came later — but he recalled the focus, after the attacks of Sept. 11, 2001, on preventing intentional destruction of critical Maryland infrastructure. The studies analyzed vulnerabilities at the Key Bridge and explored the feasibility of installing pier protection to reinforce the structure.

In the 1980s, federal agencies encouraged bridge owners nationally to evaluate spans for vessel collision and, in recent decades, local Maryland pilots discussed the possibility of a ship striking the Key Bridge, or its southern neighbor, the Chesapeake Bay Bridge near Annapolis.

These early 2000s, state-commissioned reports are the latest revelation into warnings unheeded as various government administrations balanced priorities and budgets while the Key Bridge sat insufficiently protected from an ever-growing class of cargo ships.

In the dizzying months and years after the 9/11 attacks, the Democratic administration of Glendening and then his successor, Republican Bob Ehrlich, focusing on preventing and protecting infrastructure from acts of terror. Efforts were centered, given the nature of the 9/11 attacks, more on bombs and airplanes than errant ships.

Glendening, who served as governor from 1995 to 2003, acknowledged that he and others could have done more to follow through on Key Bridge protections.

“I think we should have been much more aggressive on a multi-administration and multi-level government effort and we weren’t,” Glendening told The Baltimore Sun on Saturday, “and a lot of it was start-and-stop, studies and discussions, but very little real action.”

Money, as it is wont to do, likely played a key role.

Robert Flanagan, the Secretary of Transportation under Ehrlich, did not recall the studies, but told The Sun: “The transportation budget when we were there was full of priority issues.”

After the 9/11 attacks and threats to California’s Golden Gate Bridge in 2001, engineering consultants created a slideshow analyzing five Maryland bridges and then issued two reports on the Key Bridge for the Maryland Transportation Authority, looking specifically into “intentional destruction.” The first report, published in August 2002, studied vulnerabilities like “explosive threats” and “ship impacts,” and the second, from March 2004, focused upon the feasibility of “stand-off pier protection” at the span. The slideshow and reports’ 160 pages were obtained Friday by The Sun in a Maryland Public Information Act request but were heavily redacted.

The first study came with about five months remaining in Glendening’s time in office and the follow-up report arrived about a year into Ehrlich’s term.

The inaction that followed highlights the competing priorities state agencies must weigh and the potential difficulties in moving forward on a bridge-fortification project that would ostensibly have little immediate benefit — unless the unthinkable happened. It took officials in Delaware decades to generate support and funds for a $95 million effort, which began last year, to install protections around the Delaware Memorial Bridge.

The Key Bridge was ultimately felled by a 100,000-ton cargo ship named the Dali that lost power and accidentally plowed into one of the bridge’s vital support piers, killing six construction workers and eliminating the span. The National Transportation Safety Board’s investigation into the incident is ongoing.

What, precisely, the 20-year-old reports found, and whether they included how much sufficient protections would have cost, for example, remains unknown. The studies were redacted, in part, for security reasons.

Ehrlich served as governor from 2003 to 2007 and neither his Secretary of Transportation, Flanagan, nor the transportation department’s deputy secretary during that time, James Ports, recalled the studies.

The 2004 report on potential pier protection of the Key Bridge did not make it from the Maryland Transportation Authority’s engineers up to consideration by the leaders of the transportation department, Ports said.

“In this case, apparently, the engineers determined it was not a viable threat,” Ports said in an interview Monday.

Both reports, completed by engineering consultants Wallace Montgomery & Associates in partnership with Ammann & Whitney, were submitted to David LaBella, a project manager with the transportation authority. LaBella, who now works at Wallace Montgomery, declined to comment.

Ports said officials did take extra measures to surveil bridges, mostly from intentional attacks, like a bomb, but focused more efforts on airplanes “because that’s how they attacked us last time.” Following the revelation of a 2006 airplane bomb plot originating in London, Ports and other officials traveled to Israel for a week of security training.

“You look at the entire landscape of all of the transportation things that could occur and you try to figure out which ones have the most potential of occurring and those are the ones you harden first,” said Ports, who also served as Secretary of Transportation during Republican Gov. Larry Hogan’s administration, “so that’s what we did.”

The bridge did have some pier protection in the form of small “dolphins,” or artificial islands meant to deflect a ship from bridge supports. In the decades since the span was constructed in 1977, though, ships have grown exponentially in size, making them much greater threats to infrastructure. Ports and others have noted that the bridge, constructed 47 years before its demise, was not built to withstand a hit from the massive cargo ships that now regularly call on Baltimore.

Asked if Maryland, equipped with the knowledge of larger ships, could have physically reinforced its bridges in more recent years, Ports instead pointed to pilots and tugboats, which are non-structural measures that can be taken to prevent vessel collision.

Ships like the Dali are required to be guided by licensed, expert pilots when in Maryland waters. Tugboats do assist them in and out of their berth in port, but were not required to assist vessels under the Key Bridge. In some cases, ships were escorted by tugboats under the bridge, but the Dali was not.

“Keep in mind that the ships have their pilots,” Ports said, “and they could also have tugs [that] move those ships back and forth. So that’s another way to counter that, and that’s something that ship owners would have to pay.”

In its nascent years, a Key Bridge barrier was struck by a 390-foot ship (the Dali is 984 feet long, by comparison), causing $500,000 in damage in 1980 and, earlier that year, a ship had knocked down the Sunshine Skyway Bridge near Tampa, killing 35 people. At the time, a Maryland official said that if the Key Bridge or Bay Bridge suffered a similarly direct hit, those bridges, too, would collapse.

A Baltimore Sun article in May 1980 noted “a repeat of the Tampa Bay collision could happen in the Chesapeake Bay.”

“It would be foolish to say no,” George Quick, the president of the Association of Maryland Pilots, said at the time, according to The Sun.

So, the threat of calamity had been known since at least then with a renewed focus coming in the early 2000s. Both Glendening and members of the Ehrlich administration noted that leaders in the years since could also have installed better protections.

Engineers have differed as to whether a fortified pier protection system could have stopped the inconceivably forceful cargo ship from collapsing the span. This summer, the Maryland Transportation Authority said it was exploring a project to boost pier protection of the Bay Bridge by winter 2027-28. The initial budget is $145 million.

That’s a substantial chunk of money. And with transportation projects, like anything, cost is always a factor.

“We didn’t kill it. We didn’t turn it down. We never said this is a bad idea,” Flanagan said of the early 2000s reports. “It was a question of finding a place in the budget to work on it and unfortunately no one did.”

Glendening said he still has a “genuine concern” of huge cargo ships causing further damage to infrastructure. If he “could wave some kind of magic policy wand,” he said, he would retrofit “our most endangered bridges” with protections and, in some cases, simply rebuild them.

The transportation authority plans to identify the builder of the replacement Key Bridge by Labor Day and the construction project is anticipated to cost $1.7 billion, which will be primarily, if not fully, federally funded. It is expected to have more robust pier protection than the old span.

Baltimore Sun reporter Dana Munro contributed to this article.