SAN FRANCISCO — Jerry Lee ran his battered hand along the side beam of a 35-foot extension ladder.

This particular workhorse of the San Francisco Fire Department — from Truck 5, Station 5 — was showing serious wear and tear. It had been dropped on the job in January and could no longer be trusted to bear a firefighter’s weight.

“There’s a crack they’re concerned about,” Lee said, tracing the offending scar with his thumbnail. “I’ll open the break so I can get some glue in there. Then I’ll clamp it back together. … If they don’t destroy the ladder, I can repair any part of it, and it’ll go out as good as the day it was built.”

Only two dozen or so fire departments in America still swear by wooden ladders for their strength, safety and durability. Most are in California, and all but one buy their climbing gear from a company in Chino, Calif. The lone holdout is San Francisco, which still manufactures its own.

The department’s 400 or so ground ladders are made of old-growth Douglas fir, harvested from eastern slopes in the Pacific Northwest, where limited light makes the wood grow dense and strong. All of them have been built or refurbished by a three-man crew with singular skills.

Ladder craft

Those same men also turn out the 163-year-old department’s metal nozzles and hose couplings, its hydrant wrenches, fire bells and the ornate eagles that adorn them. They build and maintain 13 types of ladders and track the department’s long-lived inventory in a linen-bound book nearly a century old.

And when firefighters come up with ideas to improve equipment — a redesigned forcible-entry tool or a pressure-reducing valve for fire hydrants — their sketches end up in the drafty shop between the wholesale produce market and San Francisco Bay.

At least they do now.

The shop’s patternmakers, Lee and Qing Du, are nearing retirement. And the city has yet to engage in the lengthy process of finding and training successors. Within a year, refinisher Peter Misthos could be left alone to carry on the San Francisco tradition.

Ladder-making is “part science, it’s part art, it’s all craftsmanship and experience,” shop supervisor Michael Braun said. “To find replacements for gentlemen like this is not easy.”

In the wood shop, perfumed by pitch and lightly coated with a fine layer of sawdust, Braun sorted through a stack: There are boarding ladders for fireboats, with hooks designed to fit over a gunwale; 50-foot extension ladders to scale the sides of multistory buildings; and so-called baby extension ladders for access to the attics of old Victorians.

Most fire departments switched to aluminum ladders half a century or so ago, Braun said, because they are cheaper and require less maintenance. Some firefighters believe that the metal models are lighter and easier to handle.

But handcrafted wooden ladders live on in San Francisco in part because of the city’s uncommon combination of geography, architecture and urban design.

Old, wood-framed houses stand cheek-to-jowl. The streets are narrow and twisty, and many run beneath a canopy of electrical wires that power buses, streetcars and trolleys.

“A wood ladder,” Braun said, “does not conduct electricity. In case you have a ladder up and you were to strike a live wire, you won’t get electrocuted.”

It’s a danger that retired Battalion Chief William C. Peters of the Jersey City (N.J.) Fire Department understands all too well.

In the 1990s, Jersey City firefighters were called to a blazing tenement. People were trapped on the third floor, screaming for help. As two rescuers struggled to hoist an aluminum ladder in the snow, a third firefighter jumped in to help. When they swung the apparatus toward the building, it struck a 4,800-volt primary power line.

All three firefighters were hit with a jolt of electricity, Peters recalled. One of the men died. Another lost toes and a finger. The third was blown clear. “His heart rhythm was screwed up for a while,” Peters said.

Longevity is another plus for wood. Although the life of an aluminum ladder is 15 to 20 years, Braun said, San Francisco’s oldest wooden ladder still in continuous service was made in 1918.

Known by the serial number B3, the 50-foot extension model weighs in at 350 pounds and is no outlier.

The cross-hatched pages of the ladder shop’s log book are a testament to wood’s durability: C1, a 35-foot straight ladder, was made on Aug. 15, 1919, and is still in service with nothing more than basic maintenance. C5, built in 1920, was destroyed on the job 51 years later. C7, also of 1920 vintage, was rebuilt and put back to work.

‘A lot of history’

Lee figures that a good 80 percent of the work done in the cluttered shop is repair and maintenance of the Fire Department’s functional history. Boards of Douglas fir are stacked against the wall to cure. There are piles of rungs made of hickory and ash. Molds for metal parts lean against a workbench. Nothing is thrown away. Everything is reused.

“There’s a lot of history in this shop,” Braun said. “The guys that all work here are keenly aware of how important what they do is for the citizens, the fact that these ladders are designed to go into buildings, put out fires, save people’s lives.”

The most famous fire in the city’s history — in fact, the worst U.S. blaze ever — was the conflagration of 1906, which followed the far-more-famous San Francisco earthquake.

Fire Chief Dennis Sullivan was killed in the quake, and the military stepped in to help fill the breach. The Army Corps of Engineers decided to create fire breaks by dynamiting buildings along Market Street and Van Ness Avenue.

“The more buildings they dynamited, the more fires they started,” said Braun, who also is on the board of the San Francisco Fire Department Museum. “They ended up becoming their own worst enemy.”

By the time it was over, an estimated 28,000 buildings were destroyed, about three-quarters of the city by some counts. More than 3,000 people died.

But that wasn’t the first time that the better part of San Francisco burned to the ground. The first “great fire” began Christmas Eve 1849, in a gambling den called Dennison’s Exchange. The fledgling city, which had been slapped together out of salvaged wood and canvas, was destroyed in mere hours.

Rebuilding went quickly — there was, after all, a gold rush on. But over the next 18 months, the painful cycle of burn and build repeated itself five more times.

San Francisco’s official seal includes a spread-winged phoenix, the mythical bird that rises from the ashes.

“The San Francisco Fire Department has got this unique history,” said Glenn Corbett, associate professor of fire science at John Jay College of Criminal Justice. “And the ladder is a part of that.”