Groton - As a young Navy lieutenant j.g., Millard S. Firebaugh was driving along Storrow Drive in Boston 40 years ago today when he heard on the radio that the submarine USS Thresher had been lost during sea trials.

Firebaugh, who advanced to rear admiral before retiring from the Navy and taking a job as vice president and chief engineer for Electric Boat, was involved in the search for the Thresher and helped enforce the Sub Safe rules the Navy promulgated in the wake of the disaster.

The loss of the first of a new class of attack submarine was a setback for the Navy, but the Sub Safe program is seen as one of its crowning achievements because it has engendered a four-decade focus on safety.

"It's fundamental to our culture at Electric Boat that we have a very, very intense regard for these principles, and their effective administration," Firebaugh said. "Thresher was the watershed event that focused us on these principles of maintaining the integrity of the ship and the ship control functions."

Brian Burdick, program management chief at EB, said every employee must undergo annual Sub Safe training, which includes a 20-minute video that emphasizes why the safety procedures are so important.

In addition, the Naval Sea Systems Command comes in once a year for a full review of the safety procedures and to make sure workers are following the approved procedures.

"That happens here at Electric Boat, at Newport News (Shipbuilding in Virginia), at the four public Navy yards, and at any place in the world that works on submarines," Burdick said.

On the day the Thresher was lost, Burdick was a student at Fitch High School in Groton and his father was a ship's manager on the USS Alexander Hamilton, which was out on sea trials that same day.

"The first word that came back was that a submarine had been lost, but there was no word which one it was," Burdick recalled. His mother was worried until word came that the Hamilton was returning to port.

"My dad has a pretty vivid recollection that they were at depth, came back up, put up the antenna to communicate with the support ship, and picked up all the message traffic going back and forth," Burdick said. "There's not a day, not a night, not a weekend that goes by that I don't think about Thresher."

James Noonan, EB's director of Sub Safe and quality assurance, was in elementary school 40 years ago, but he keeps a poster in his office - a reprint of the front page of The Day that announced the loss of the Thresher.

"I was in the third grade and I lived in a small town in Massachusetts," Noonan recalled. "My teacher stepped out in the hallway, then stepped back in and said a United States Navy submarine from Portsmouth, New Hampshire, had been lost at sea."

The teacher had to leave the class because of fear for her uncle, who was stationed in Portsmouth, though it later turned out he was not aboard the Thresher.

"But that left an impression on me for the rest of my life," Noonan said. "I've been with Electric Boat 24 years, and spent most of that time in the quality assurance program. It's something that I've stayed focused on through my entire career."

Coincidentally, as the 40th anniversary of the Thresher disaster approached, more than 40 Navy officials conducted a week-long inspection last month to make sure the Virginia, which will be launched this year and commissioned next year, meets all Sub Safe standards. Like the Thresher, the Virginia is the first of a new class of boat.

The inspection is on a pass-fail basis - if any flaws had been uncovered the program would have been given a failing grade. The Virginia received a pass, and EB President Michael W. Toner gave a closing speech that stressed the importance of the audit.

"He really showed our commitment to Sub Safe, to each and every person in that room," Noonan said. "It really permeates the entire organization."

Thresher breaks apart

The Thresher was built by Portsmouth Naval Shipyard in Kittery, Maine, and commissioned in August 1961, the first of a new class of hunter-killer submarine with a new type of sonar and the ability to go faster and deeper than anything before it.

After trials in the western Atlantic and Caribbean through 1962, it returned to the shipyard for an overhaul that lasted until the following spring. On April 10, 1963, in the company of the rescue ship Skylark, it began its deep-dive trials in an area about 220 miles east of Cape Cod.

At 9:13 that morning, the Skylark received a signal that the submarine was experiencing "minor difficulties." Minutes later, the Skylark received a series of garbled messages, and at 9:18 a.m. its sonar picked up the sounds of the Thresher breaking apart.

The submarine had gone down in about 8,500 feet of water, killing the 112 sailors and 17 civilians on board.

A subsequent investigation showed that the most likely cause was a leak in a silver-brazed joint on a section of pipe in the engine room, which sprayed seawater onto an electrical panel and caused a reactor shutdown.

Because of a design flaw, the system that was designed to blow out the submarine's ballast tanks froze up, and the Thresher's emergency propulsion motor was inadequate to get it to the surface.

The Navy found a variety of problems that contributed to the disaster:

* The regulations governing the design and construction of the nuclear portion of the submarine were considerably more stringent than the rules governing the rest of the boat, even though a failure of non-nuclear components could just as easily lead to the destruction of the ship.

*Where a pipe joint was inaccessible, the builders used a different and less reliable brazing method than was used on accessible joints.

*A new type of testing method using ultrasound to inspect welds was found to be difficult and time consuming, so the builder did not use it on all joints

- even though 20 of 145 joints that were tested failed the tests.

*The Navy set strict specifications for the equipment used in submarines, but did not confirm that all material that was used met the design specifications. In one critical component, the manufacturer changed the design without having it subjected to a rigorous review.

Congressional hearings held

The wreckage of the Thresher was located that summer, but the Navy wanted a better look, and it made plans to mount another search.

"The Navy continued the operation in the summer in 1964, and I participated in that search, and I've been hooked on submarines ever since," Firebaugh said.

Firebaugh keeps in his office a transcript of the congressional hearings into the sinking, and the legislation that directed the Navy to take measures to prevent a recurrence. The Navy's response was a Dec. 20, 1963, letter that established the Sub Safe program.

Sub Safe set technical specifications for the design, construction, repair and operation of nuclear submarines, each of them deliberated at length and setting requirements for any systems that could, by its failure, lead to the loss of a ship.

Though the regulations were complex, the principles they embodied were simple: Keep the water out of the "people tank" while preserving propulsion, steering and other systems that control the movement of the ship.

Over the next decade the Navy issued almost 40 updates to the letter until finally, on Dec. 20, 1974, it issued its first Sub Safe manual.

Firebaugh said the Sub Safe program has, over the years, become such a part of everything associated with submarines that it is embedded in everyone's consciousness. Numerous Navy audits help to reinforce it on a regular basis.

In addition, he said, one of the hallmarks of Sub Safe is its demand for accountability. Every part that goes onto a submarine can be traced back to the company that bought the raw materials that went into its manufacturing process. Each person who works on a boat, and the work they did, must be documented.

And after new construction or major repair, an admiral in Naval Sea Systems Command must certify that the work met all program requirements.

"The responsibility for the final decision rests very squarely on the shoulders of an individual who stands up and says, 'I have reviewed it and this submarine is ready to go to sea,' " Firebaugh said.

Despite its emphasis on being able to detail every step taking in construction or repair, however, Sub Safe is much more than certifying a valve or a weld, he said.

"What sets it apart from most of the other certification and safety programs is it concentrated very specifically on the kind of casualties that could cause the loss of the ship" Firebaugh said. "And I think that's been one of its strengths - it did not try to encompass too much, so it never lost its focus."