Halfway to Safety: The Tale of a Little Clip and a Big Net

By Amy O’Hair

Note: This article does not include anything about the new net that was recently installed on the Golden Gate Bridge to prevent suicides.

Sometimes in my research I come across people whose lives have had a real impact on San Francisco, but whose stories have never been told; the best of those stories shine a new light on an old familiar subject. This post is about a little invention—and the person who designed it—which played a part in dramatically improving worker safety during the construction of the Golden Gate Bridge in 1936-1937. A small metal clip, invented for the purpose, enabled the fabrication of the giant nets that caught falling workers. Such nets subsequently became standard safety gear on similar work sites—a worldwide phenomenon that prevented an untold number of deaths, and a story that is anchored in San Francisco ingenuity and initiative.

Although I had found out about the man who invented the clip—he was the father of the first owner of my Sunnyside house—I am now prompted to put the story together after visiting a new local bar and restaurant, The Halfway Club, on Geneva Avenue. [January 2025: The bar was nominated for an important award.]

The place was named by its owners, Ethan Terry and Greg Quinn, in honor of the club formed by the construction workers who survived falling into the net: The Halfway to Hell Club.

More about that later. First, the net and how it got made.

A Revolutionary Net

Chief engineer for the Golden Gate Bridge, Joseph B Strauss, was safety minded from the beginning of the project, insisting on hardhats and safety lines—and firing any worker who refused to comply.^[1] His concern for the well-being of the workers extended to offering sauerkraut juice for their hangovers.^[2] Then in early 1936, his principle assistant engineer, Clifford E Paine (1887–1983), pressed Strauss to install nets for worker safety.^[3] Current safety standards like guardrails, personal harnesses, or floatation devices were decades away. The idea of a net for worker safety during construction was altogether new, but Strauss agreed to it.

When construction on the bridge began in 1933, the general rule of thumb was that a bridge project would kill one worker for every million dollars spent—which in this case would have been thirty-five men. The Bay Bridge, which began construction in mid-1933, had already lost twenty-two men by 1936.

When Strauss announced the plan for the net in June of that year, he had lost no workers up until then, and aimed to keep his safety record exemplary. The net would be “the most elaborate and expensive safety device ever conceived for a major construction project.”^[4]

The estimated cost of the net was $126,000. As well as being an ethical choice, the decision made good business sense; deaths and injuries cost money. One important impact of the net turned out to be an increase in the speed of work—workers felt more secure and worked faster.^[5] That helped the bottom line by preventing delays in completion.

A Knotty Problem

As a human technology, nets are ancient—long predating the invention of the wheel. Knotted nets were used by Stone Age fishers, at least by eight thousand years ago—although some archaeologists think that fishing with nets could go back 29,000 years. Nets do something unique—catch something without damaging it. Nets under circus performers have been used since 1866,^[6] but the idea of using them where the risk of falls endangered construction workers was new.

The question was how to construct a net on the scale needed. The old, indeed very old, way of making nets by knotting the filaments together at each and every crossing was stupendously impractical for anything near the size to do the job. When it was finished, the net would be as wide as Market Street plus ten more feet, and would have stretched from Kearny to Van Ness streets.^[7] As always, time was money, and fabrication of the net needed to happen quickly if it was to be installed and do its job of saving lives without slowing construction of the bridge.

On 8 June 1936, Strauss announced his intention to install the safety net. A month later, Bethlehem Steel Company offered to construct it, on the condition that the Golden Gate Bridge and Highway District paid $82,000 of the $126,000 total cost. A generous offer? Later it was revealed that their offer stipulated that Bethlehem got to keep the net after it had served its purpose for construction of the bridge.^[8]

The net took less than three months to complete, from Strauss’s announcement to the day it was installed. On 2 September, workers were shown testing it—and just for good measure, 400-pound weights were dropped into it, to see if the net broke. It held: a minor engineering marvel.^[9]

Strauss, known for his outsized ego, never lost an opportunity for touting his record on safety.

“My efforts alone installed the safety net,” he said.^[10]

Not quite, Mr Strauss. Other people played their parts. How did this marvel become a reality?

A Man with a Clip

A machinist and inventor, Dennis Frank Larkin (1875–1947) owned a small company producing sheet-metal items to order, Larkin Specialty Manufacturing, at 268 First Street in San Francisco. The firm made a variety of things, including coin banks, specialty washers for the burgeoning automobile industry, suitcase parts, and hard hats.^[11] At some point shortly after the decision about the net was made, Larkin was tapped to invent some way to secure the manila rope at the intersection points—without knotting.

The clip he invented was formed of two die-stamped pieces of sheet metal, crimped together at four points, and featuring little gripping indentations. View Larkin’s patent with text (PDF).

The manufactured clips were about one inch in diameter. Larkin’s company must have cranked them out at breakneck speed, as the final nets would employ many hundreds of thousands of the two-part clips.^[12]

But Larkin’s rope clip couldn’t produce the enormous net by itself. One of the bridge engineers, George William Hanson (1881–1977), simultaneously invented a device for actually constructing the net sections. The patent drawings clearly show his device employing Larkin’s clip, applied to the lengths of rope at intervals. View Hanson’s patent with text (PDF).

The patent text did not specific the size of rope or the size of intervals, but for the Golden Gate Bridge, half-inch manila rope secured into six-inch squares was the chosen design.^[13] Despite being a large-gauge net, from a distance it had a gauzy appearance, so vast was the scale.

Hanson had a long and interesting career in engineering, working on projects across the country, including the construction of the Mackay Radio Tower on the far eastern end of Long Island, New York. According to his obituary, Hanson received a commendation from President Franklin D Roosevelt for his design for the Golden Gate Bridge net.^[14]

No such honor came to DF Larkin, although his obituary mentioned the little clip and the part it played in the innovative net.^[15]

A Tinkerer and a Rogue

During his career, DF Larkin filed numerous patents for small useful things, but his little clip for the Golden Gate Bridge net is the thing he should be remembered for. His other inventions range from quirky—a strange pod-like perambulator for infants—to the possibly quite personal, such as cigar-smoking apparatuses designed to prevent something called ‘sweating’ (one gets a whiff of a serious nicotine addict). Other inventions are more ordinary—like floor-wax applicators. One is whimsical, a device for taking the middle out of a banana and then filling it with ice cream. My list of Larkin’s fifteen patents, with links for viewing the PDFs, is found here.

DF Larkin’s grandson turned out to share his bent for melding the practical with the imaginative. Walter E Larkin (1923–2007) (pictured right) grew up to become a scientist working on early guided missiles for the military, the pioneering satellite project Explorer I, and giant antennas for the Department of Defense’s Advance Research Projects Agency (later DARPA).^[16]

Walter said of his grandfather, who was known as Frank by his family:

“He was a bit of a rogue.”

In a memoir, Walter recounted a family story about how Frank, as a young man in Kansas, would take his bicycle to nearby towns where no one knew him. He’d play the fool, drum up a wager, beat every competitor in a race, and ride home with the take.^[17]

Frank Larkin married his wife Pearl Marti in Texas in 1899, and moved the family to San Francisco by 1903. He first worked as a carpenter in South of Market shops. Immediately after the 1906 Quake, he stayed to fight fires, while his wife and four children fled to an empty lot they owned on Bernal Hill, on Ripley Street.^[18] There was plenty of work for a carpenter after the Great Fire. When the peak of reconstruction was over, he turned to sheet metal, and founded his company, Larkin Specialty Manufacturing in 1912.

The first premises for the firm were in a newly built light-industrial building on Valencia at 26th Street, where the Salvation Army store is now (that’s what those massive skylights were for). But the buzzing heart of San Francisco manufacturing was in the South of Market district then, so he soon relocated the company to First Street, later constructing a big new building for the company at number 268 (now gone).

DF Larkin retired in 1946 and died in 1947. He was eulogized for his virtues of character, his career and philanthropic donations, his service in the Spanish-America War—and for the rope clip for the Golden Gate Bridge net.^[19] After his death, the company lived on, relocating to San Mateo County in 1954 and acquiring two other companies in 1961, before being bought by SFO Helicopter Airlines in 1968.^[20] In 1972, it was failing and was put up for public auction (an ad for which I include largely because of the groovy typeface).

Let’s return to the elite group of construction workers who were saved by the net.

Halfway to Hell, and Back

Bridge workers were in a class of their own—the work was dangerous and took an iron nerve. Death shadowed you everywhere as you worked on the beams. At the mouth of the Bay, there were the added hazards of beams slippery from fog and strong winds.

“A bridgeman who fell to his death was said to have ‘gone to hell’ so the men who survived their falls into the net decided to call their group the ‘Halfway to Hell Club’.”^[21] All told, in the nine months from its installation until the completion of the bridge in May 1937, nineteen workers fell into the Golden Gate Bridge net, and thereby qualified for membership in this elite band.

The first to fall was George B Murray, a carpenter, about six weeks after the net went up. On a day with gusts up to seventy miles an hour buffeting the workers, he and another worker, Ulysses S Brown, were struck by a traveler, a steel-carrying car, that came down upon them.^[22] Brown managed to stay put, though his leg was broken, but Murray plunged thirty feet into the net, both his arms badly injured by the impact of the traveler car. He would be hospitalized for months to come.

Three days later, Al Zampa fell. Later to become a famed labor leader, Zampa is the most well-known of all those who fell into the net. On a wet and foggy day, his foot slipped on the beam and he somersaulted downward into the net. Unfortunately it was badly positioned over rock. He told the story in an interview later:

“I was startled but not really afraid. I figured the net would catch me and I would bounce up and land on my feet, like in the circus. Well, the net went down to the rocks. The first drop, when I hit the rocks, didn’t hurt too much, it just kind of knocked the wind out of me. I came up and then went back down. That’s went I had the pain.”^[23]

Zampa broke three vertebrae in his back, and fractured his pelvis. They put him in a body cast and he spent three months in St Luke’s Hospital, where George Murray was also still recuperating.

After his accident, the net was rigged better to avoid a faller getting grounded during a fall. “Why didn’t they do that in the first place?” Zampa later asked; he was a labor advocate who was always vigilant in the face of management negligence that endangered workers.^[24]

Bad Luck in Triplicate

Two days after Zampa’s fall, a third worker fell in. But this incident included a tragic death as well. A crane’s travelling arm came loose, and the crane toppled, crushing Kermit Moore, age 23. Miles Green, working beside him, was struck by a snapped cable and fell thirty-five feet into the net, which saved his life.

Over the next two months, six more men fell into the net, but the incidents were no longer so newsworthy. On 2 December 1936, the tenth worker fell, a painter named John Perry.^[25] 

Two weeks later, the Halfway to Hell Club was formed. Six of the men who had fallen—Paul H Terry, Jack Miller, Edward Stanley, Miles Green, James E Roberts, Jack J Delaye—gathered at Al Zampa’s bedside at St Luke’s Hospital, jointly decided their ordeal merited recognition, and christened their club.^[26] The three other fallers—George Murray, Ward Chamberlain, and John Perry—were still convalescing from their injuries.

On 14 December 1936, the six club members not in the hospital “gathered near the San Francisco anchorage to celebrate surviving their fall.”^[27] An unnamed Associated Press photographer hauled his large-format camera up onto the beams with them, and took this fabulous shot, later scrawling “GG Bridge Halfway Club” on the back of the negative.^[28]

Of course the newspapers—like the bar I mentioned at the opening of this article—wanted a more family-friendly tone, and so in all the published reports about the newly formed group it was just called The Halfway Club.

The Unknown Members

At the beginning of January, the eleventh member of the club, Pete Patterson, fell in the net, and “after a few bounces on the stout cord, climbed back up to his work.”^[29] After this, no other falling construction worker caught by the net was named in the newspapers. There was likely an effort to staunch publicity by management, as well as a stated prohibition on jumping into the net, as deliberate falls had become attractive to some workers. Workers threw things into the net, and some dove in to retrieve them. “They’d jump down in there for kicks,” related one worker later. “About once a week the net had to be cleaned out entirely.”^[30]

Today, there is no known complete list of all the workers who fell. I assembled what details I uncovered about all the named workers in the course of my research in this list for the Halfway to Hell Club, but there remain many unknowns, such as basic biographical information about most of the men.

“No one is really sure what became of the nineteen men,” according to John V Robinson, author of Spanning the Strait. He goes on to note that the original idea for the club to meet up once a year to commemorate surviving their falls into the net did not go to plan. ^[31] Bridge workers tended to be itinerant, moving where the work is.

Johnny I Hardly Knew Ye

One man made later an effort to try to find the members of the club. In the late 1940s, Eric Leader Pedley (1896–1986) had picked up the mantle of safety-net manufacturer. He founded Pedley-Knowles & Company in 1947, and became the leader in manufacturing worker safety nets (now called PK Safety and still in business). During the 1950s, he patented three methods for making rope nets, updating Larkin’s rope clip by using fiberglass and plastic-based technologies—a natural evolution. (View his patents here and here and here.)

In 1963, around the 25th anniversary mark of the Golden Gate Bridge, Pedley set about re-assembling the Halfway to Hell Club, and tried to trace what had become of the men who fell into the net. He had some correspondence with Al Zampa (see below), the most prominent member, and apparently the only one that Pedley could locate. Pedley, a well-connected businessman, solicited sponsorship from an array of backers—construction management companies, insurance and safety agencies, and some union involvement.

But nothing seems to have come of the drive to reunite members of the vaunted club. Bridge workers are an independent-minded breed. Perhaps it is that spirit that is a source of inspiration for the San Francisco bar that took its name from the club, The Halfway Club.

This very short video shows ten members of the club, captured perhaps in early 1937. A piece of the net is displayed up close to the camera’s lens, making it look larger that it really was—six-inch squares, with one-inch rope-clips.

(Source: “Worker Safety During Construction of the Golden Gate Bridge”)

The Day the Net Broke

There is one more incident in the life of the net to relate in order to finish the story. By mid-February 1937, the net had saved at least a dozen workers from deaths in the waters of the Bay, and only one worker had died. Construction was due to be finished by the end of May, and the project was on a path to setting a record for worker safety. But then one catastrophic accident put a huge dent in that record, and seemed to confirm the old superstition of bridgeworkers: the “the bridge demands life.”^[32]

On 17 February 1937, a five-ton scaffold broke loose and it plunged into the net, taking twelve workers with it. The net tore, having never been designed to catch something so heavy. Two workers were rescued from the water, badly injured. Ten men died in the Bay, and many of their bodies were not recovered for days.^[33] Robinson notes that “neither of the two men who were fished out of the water alive that day appear to have been admitted into the Halfway to Hell Club.”^[34]

A thirteenth worker kept himself from falling by grabbing a broken caster and hanging on for dear life. He was rescued from above, his pipe still clenched in his teeth, but any notion of celebrating his brush with death was overshadowed by the deaths of ten of his co-workers.^[35]

Improperly sized bolts were at fault, confirmed later by the coroner’s jury.^[36] The problem had already been identified and that very morning a safety inspector was en route to the site to look into the matter. The bolt holding the scaffold on was “too damn short,” a known risk.^[37] These were not deaths and injuries that the net could have prevented—it was a situation that only needed greater caution in the face of a known danger to workers.

The net was replaced within two weeks, and work went on.^[38] By the completion of the bridge on 27 May 1937, eleven lives had been lost—the ten who fell in the scaffold incident plus the one man lost the previous October.

Ever a Grave Matter

Regarding fall protection for workers, a friend of mine who works in occupational safety told me recently:

“It’s still a big issue. Gravity is here to stay.”

Every year, hundreds of workers still die in falls at work—even as there are many more methods for preventing falls now, such as harnesses with retractable cords that don’t get tangled underfoot. Nets are still used on construction sites, but often they have a second layer of fine-gauge netting that is designed to prevent tools from falling on passersby or other workers. Even for that issue, there is tool tethering with retractable cables. Nets are no longer a core fall-protection measure.

When I did my initial research in 2015, Eric Pedley’s company PK Safety still carried safety nets—still with a six-inch gauge, but fabricated in synthetic rope with a metal strip securing each intersection. That net had disappeared from their website by the time I returned to the subject to finish this story this year.

Occupational Safety and Health Administration (OSHA) often cites and fines companies for failing to provide workers with fall protection—it is the most frequent reason for a citation.^[39] Fines can be very steep, as a quarter of such falls result in death or serious injury. Management cost-cutting that results in OSHA rule violations and increased risks for workers remains a problem, but the overall picture of worker safety is better now than ninety years ago when the construction site at the Golden Gate Bridge got its landmark new net.

 

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Bibliography

Books

Cassady, Stephen. 1990. Spanning the Gate : The Golden Gate Bridge. Special edition. Mill Valley, California: Squarebooks.

Dillon, Richard H., Don DeNevi, and Thomas Moulin. 1979. High Steel : Building the Bridges across San Francisco Bay. Millbrae, Calif.: Celestial Arts.

Historic Photos of the Golden Gate Bridge. United States: Turner Publishing Company, 2008.

Lundvall, Börje. 2015. The Halfway to Hell Club : In Search of Lindros and the Other Men Who Fell into the Gate : Immigrant Stories and American Heroes. [Karlstad], Sweden: Lundvall Konsult och Design.

Robinson, John V. 2005. Al Zampa and the Bay Area Bridges. Charleston, SC: Arcadia Pub.

Robinson, John V. 2004. Spanning the Strait : Building the Alfred Zampa Memorial Bridge. Crockett, Calif.: Carquinez Press.

Starr, Kevin. 2010. Golden Gate : The Life and Times of America’s Greatest Bridge. 1st U.S. ed. New York: Bloomsbury Press.

Van der Zee, John. 2000. The Gate : The True Story of the Design and Construction of the Golden Gate Bridge. Lincoln, NE: iUniverse.com Inc.

Articles

“Construction.” Golden Gate Bridge Highway and Transportation District. https://www.goldengate.org/bridge/history-research/bridge-construction/construction/ Accessed 1 Aug 2024.

Fireman, Janet, and Shelly Kale. “Bridging The Golden Gate: A Photo Essay.” California History 89, no. 3 (2012): 9–87. https://doi.org/10.2307/23215874 .

“Halfway to Hell Club.” Wikipedia.org https://en.wikipedia.org/wiki/Half_Way_to_Hell_Club . Accessed 23 Jul 2024

Larkin, Walter, and Kate Larkin du Plessis. “Actually, I AM a Rocket Scientist: Memoirs of a Space Age Pioneer.” (2008) https://memoirpublishing.com.au/assets/extract-from-walter-larkin.pdf

Moffitt, Mike. “He fell ‘half way to hell’ off the Golden Gate Bridge and became a legend: The story of ironworker Al Zampa.” SFGate.com. https://www.sfgate.com/local-donotuse/article/halfway-to-hell-Golden-Gate-Bridge-Al-Zampa-14560813.php Accessed 2 Aug 2024.

Pedley, Eric L. “The Why, Where and How of Personnel Safety Nets.” The Journal of the American Society of Safety Engineers 9, no. 10 (1964): 20–23. http://www.jstor.org/stable/45439017 .

Standen, Amy. “75 Years Ago, A Deadly Day On The Golden Gate.” NPR.org, 27 May 2012. https://www.npr.org/2012/05/27/153778083/75-years-later-building-the-golden-gate-bridge . Accessed 23 Jul 2024.

Standen, Amy. “Life on The Gate: Working on the Golden Gate Bridge 1933-37.” KQED Quest, 27 Apr 2012. https://www.kqed.org/quest/36106/life-on-the-gate-working-on-the-golden-gate-bridge-1933-37 Accessed 23 Jul 2024.

Temko, Alan. “Bridge of Bridges.” San Francisco Examiner, 17 May 1987, pp199-201.

Publications

California Highways and Public Works (California Division of Highways)
Oakland Tribune
San Francisco Chronicle
San Francisco Examiner
San Mateo Times
Santa Rosa Press Democrat

Online Resources

Google Patents https://patents.google.com/

Ancestry.com

San Francisco Historical Photograph Collection, San Francisco History Center, San Francisco Public Library https://sfpl.org/locations/main-library/historical-photographs

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ENDNOTES

1. “Worker Safety During the Construction of the Golden Gate Bridge.” Video clip with oral history. @danieljbmitchell Youtube. https://www.youtube.com/watch?v=KLRCZAXfEa4 ↑
2. “Construction.” Golden Gate Bridge Highway and Transportation District. https://www.goldengate.org/bridge/history-research/bridge-construction/construction/ See section on Safety for details of Strauss’s measures. ↑
3. Pedley (1964) p20. ↑
4. Van der Zee (2000) p259. ↑
5. Van der Zee (2000) p263. ↑
6. First used at Chelsea Pleasure Gardens, UK, in 1866. “The Development of Circus Acts” Victoria and Albert Museum, 2013, via The Wayback Machine. https://web.archive.org/web/20160310211757/https://vam.ac.uk/content/articles/d/development-of-circus-acts/ . Accessed 24 Jul 2024. ↑
7. This practical way to understand the size of the net was detailed in: “The Deuce of Clubs,” San Francisco Examiner, 12 Sep 1936. ↑
8. “Safety Sought on Gate Bridge: Nets to Guard Workers’ Lives Planned,” San Francisco Examiner, 8 Jun 1936, p6; and “Steel Concern Offers Safety Net For Bridge,” San Francisco Examiner, 16 Jul 1936; and William Losh, “Machine to Haunt Lax Autoists,” San Francisco Examiner, 5 Sep 1936. ↑
9. William J Losh, “Safety Sought on Gate Bridge: Nets to Guard Workers’ Lives Planned by Strauss,” San Francisco Examiner, 8 Jun 1936, p6; and “Huge Life Net Installed on Golden Gate Bridge,” San Francisco Examiner, 2 Sep 1936, p11. ↑
10. “Strife Puts End to Bridge Probe,” San Francisco Examiner, 4 Mar 1937, p18. ↑
11. Larkin and du Plessis (2008) p4. ↑
12. This is my own estimate based on studying photographs, counting squares, and multiplying by the number of nets used. ↑
13. Van der Zee (2000) p259. ↑
14. “George Hanson,” Santa Rosa Press-Democrat, 16 Jan 1977. ↑
15. “Beloved Pioneer Passes On,” Pacifica Tidings and Sharp Park Breakers, 9 May 1947; and “Noted Coast Inventor Dies,” The Times (San Mateo), 8 May 1947. ↑
16. “Walter Larkin – First Goldstone Complex Director.” [An account of Walter E Larkin’s career.] honeysucklecreek.net https://honeysucklecreek.net/space_people/walt_larkin.html Accessed 1 Aug 2024. ↑
17. Larkin and du Plessis (2008) p2. ↑
18. Larkin and du Plessis (2008) pp2-3. ↑
19. “Beloved Pioneer Passes On,” Pacifica Tidings and Sharp Park Breakers, 9 May 1947. ↑
20. “Larkin Buys Two Other Companies,” The Times (San Mateo), 9 May 1961, p15; “SFO Buys Larkin Specialty,” Oakland Tribune, 19 Jan 1968, p19; and [auction ad], San Francisco Examiner, 16 Apr 1972. ↑
21. Robinson (2004) p12. ↑
22. “Damaging Gale Sweeps State,” San Francisco Examiner, 17 Oct 1936, p5; and “Net Save First Worker to Fall Off Gate Bridge,” San Francisco Chronicle, 17 Oct 1936, p17. ↑
23. Robinson (2004) pp11-12. ↑
24. Robinson (2004) p14. ↑
25. “Another Saved by the Gate Bridge Net,” San Francisco Examiner, 3 Dec 1936, p11. ↑
26. Robinson (2004) p12. ↑
27. Robinson (2004) p13. ↑
28. This photo was included in this article: Mike Moffitt, “He fell ‘half way to hell’ off the Golden Gate Bridge and became a legend: The story of ironworker Al Zampa,” SFGate.com. https://www.sfgate.com/local-donotuse/article/halfway-to-hell-Golden-Gate-Bridge-Al-Zampa-14560813.php Accessed 2 Aug 2024.A photograph taken at the same session by the same AP photographer was widely reprinted 15-17 December 1936 in various newspapers, without naming the photographer, as well as being part of the San Francisco Historical Photograph Collection, San Francisco History Center, San Francisco Public Library (image AAD-1116). ↑
29. “Bridge Nets Save Worker,” San Francisco Examiner, 8 Jan 1937. ↑
30. Van der Zee (2000) p263. ↑
31. Robinson (2004) p13. ↑
32. From Cassady (1990) p65, and quoted in Robinson (2004) p11. I trust their research and interviews with workers. ↑
33. See here for a list of the dead workers: “Construction.” Golden Gate Bridge Highway and Transportation District. https://www.goldengate.org/bridge/history-research/bridge-construction/construction/ ↑
34. Robinson (2004) p13. ↑
35. Van der Zee (2000) pp277-288; “The Thirteenth Man: Tom Casey Has Some Drinks; He and Pipe Saved, Friends Lost,” San Francisco Examiner, 18 Feb 1937, p2. ↑
36. Starr (2010) p134. ↑
37. Starr (2010) p135. ↑
38. “More Delay Permitted in Bridge Probe,” San Francisco Examiner, 25 Feb 1937, p13. ↑
39. “US Department of Labor announces national emphasis program to reduce, prevent workplace falls, a leading cause of workplace fatalities” [news release]. 1 May 2023. U.S. Department of Labor Occupational Safety and Health Administration. https://www.osha.gov/news/newsreleases/national/05012023 Accessed 3 Aug 2024. ↑