Ladder

Identity

• Names: ladder, covering as one family entry rather than three tools the stepladder (self-supporting A-frame), the extension ladder (non-self-supporting, two-section, rope-and-pulley), and the articulating (multi-position) ladder, which may reconfigure into modes expressly approved by the exact model. Do not read trestle, scaffold, stair or 90-degree modes as universal family capabilities. Regional/informal names: "steps" (UK, for the stepladder); "orchard ladder" for a splayed-leg tripod variant built for uneven ground. A platform ladder is a stepladder with a designated standing platform; its safe standing level is whatever its label and manual say.
• Family / category: portable, human-scale access equipment, distinct from fixed stairs and from scaffolding or mobile work platforms (a related but separate category; OSHA governs construction ladders under 1926 Subpart X and scaffolds under 1926.452). Split first by support type (self-supporting, leaning/non-self-supporting, articulating), then material (wood, aluminum, fiberglass), then duty rating.
• One-line: a portable set of fixed rungs or steps, either self-supporting on its own legs or leaned against a structure, that gets a person and light tools to working height.
• Explicitly NOT: scaffolding, a work platform or a lift. A ladder is access equipment and suits low-force work at a point from a stable climbing posture; it is not interchangeable across its duty ratings (a household Type III stepladder is a different tool from an industrial Type IA). The ladder-versus-platform choice is a risk-based heuristic, not a regulatory time limit (see Matching).

How NOT to use it

• Standing surfaces. Never stand on a stepladder's top cap or top step, or on any step above the highest standing level marked on the ladder (OSHA's stepladder rule, 1926.1053(b)(13), read this pass). A purpose-designed step stool, platform ladder or podium ladder may have a labeled standing surface; use only that designated surface and follow its guard and handhold instructions. "Top cap," "top step," "platform" and "highest standing level" are not interchangeable terms.
• Not-for: using the rear cross-bracing of a stepladder as a climbing surface unless the model is designed and rated for it (1926.1053(b)(14), per the original run) [manual, relayed]; leaning an ordinary stepladder against a wall like a straight ladder, unless it is designed and labeled for that mode (OSHA interpretation 2010-01-21, per the reviewer; not re-read) [manual, relayed]; using an extension ladder horizontally as a plank or platform; moving or extending a ladder while someone is on it; using a ladder for a purpose other than the one it was designed for. The original run flagged that secondary sources misattribute a "ladders shall not be used as platforms, runways or scaffolds" rule to (b)(13); the regulation text read this pass shows (b)(13) is the top-step rule.
• Dangerous: falls, electrocution, tipping and collapse. Ladder falls are among the most heavily documented workplace and consumer injury categories. The controls, from the regulation, OSHA fact sheet 3660 and the review:
  • Workholding / footing. Set the ladder on stable, level footing, or secure it against displacement; check the 4:1 angle by measurement, not by eye; secure the top and bottom where the site makes displacement possible; keep doors and access areas clear or guarded.
  • Hand position and body position. Face the ladder; keep three limbs on it; keep your body, belt-buckle level, between the side rails and descend to reposition rather than leaning out. Do not carry tools or bulky material in the hands.
  • Overreach and force. Stop and reposition, or move to a platform or lift, rather than overreach, pull hard, drill hard overhead, or work with both hands full.
  • Electrical. De-energize and verify where possible, keep at least 10 feet from overhead lines, and do not let "fiberglass" function as a safety override.
  • Roof. Treat climbing access separately from work on the roof and its own edge and fall-protection plan.
  • Articulating modes. An unlocked hinge, a climbed vertical side, an unapproved plank or an incompatible standoff changes the load path and can collapse or tip the system. Confirm every lock before climbing; use only manual-approved modes and accessories.
  • Load. User, tools and materials all count toward the rated load. OSHA's design standard builds in a safety factor over the maximum intended load (fact sheet 3660: at least four times, or 3.3 times for extra-heavy-duty Type IA), but overloading still fatigues and damages the structure, and exceeding the maximum intended load or the manufacturer's capacity is prohibited.
  • Inspection. Inspect before each use and tag and remove defective ladders from service. In a construction workplace, preserve OSHA's separate competent-person periodic and post-event inspection duty.
  • PPE. This entry does not give a PPE rule for ladder use. Fall protection on a roof or in a tree is a task-specific system, not something a ladder or a harness alone supplies.
  • Honest limit. Statistics tell how often falls happen, not how to prevent them; the controls above stand on the regulation text, the OSHA fact sheet and the review, not on any incident record this entry has verified.
• Injury burden, one dated estimate at a time (no blended figure).
  • Occupational, United States, 2011 (CDC/NIOSH MMWR, read this pass): 113 work-related ladder-fall deaths (0.09 per 100,000 full-time-equivalent workers); an estimated 15,460 employer-reported nonfatal cases with days away from work; an estimated 34,000 nonfatal emergency-department-treated work injuries.
  • Nonfatal ED-treated injuries, 1990–2005 (a peer-reviewed NEISS study, per the reviewer; PubMed was blocked this pass): about 136,118 per year on average (2,177,888 over the period), with 97.3% non-occupational applying only to cases where the injury location was recorded [manual, relayed].
  • All medical settings, 2013 (NIOSH, per the reviewer; not fetched): approximately 511,000 people treated across emergency departments, doctors' offices, clinics and other settings, not emergency rooms alone [manual, relayed].
  • The original run's blend of "over 500,000 injuries," "164,000 ER visits," "more than 300 deaths" and "97%" came from a secondary aggregator and mixes datasets, years and populations; it is withdrawn. NEISS injury estimates do not by themselves prove fatalities.
• Aluminum ladder and power-line contact. The original run cited three NIOSH FACE investigation summaries (a 1993 New Jersey case, Report 93NJ062; a 2003 North Carolina case, 2003-08; a 2003 South Carolina case, 2003-11) in which aluminum ladders contacted power lines. These came from search-result summaries, not the primary reports; recommend a direct pull before treating any wording as verbatim [manual, relayed].
• Beginner-trap: misjudging the 4:1 angle by eye; not keeping a grasp on the ladder; not extending the rails at an upper landing; setting up on soft or uneven ground without leveling or securing; treating a closed, leaned stepladder as an extension ladder; improvising with the wrong-size ladder under time pressure. The original run's ContractorTalk "Fell off my ladder today" thread came through a search summary only, and is anecdotal and unverified [manual, relayed].
• Lineage-misuse: using an articulating ladder in an unlocked or mid-transition configuration. The mechanical logic is plain (a hinge or rung lock not fully seated is a structural failure point); a specific incident or manufacturer warning for this exact failure was not located and quoted in this entry, but Little Giant's manual as described by the reviewer requires locks seated and forbids climbing the vertical side in 90-degree mode [manual, relayed].

Correct use

Two layers, kept visibly separate.

U.S. construction workplaces (federal OSHA 29 CFR 1926 Subpart X; state plans may add requirements). These are duties of employers and employees in construction. OSHA says the OSH Act does not cover self-employed workers, so they are not universal homeowner code [manual, relayed].

• Angle: non-self-supporting ladders are used at an angle where the horizontal distance from the top support is "approximately one-quarter of the working length" (1926.1053(b)(5)(i), read this pass), the 4:1 rule (about 75 degrees).
• Upper landing: for a portable ladder used to access an upper landing, the side rails extend at least 3 feet above the landing surface (1926.1053(b)(1), read this pass), or, where a ladder that long cannot be used, the ladder is secured at the top to a rigid support with a grasping device provided. The extension is an access rule, not a general rule for all ladder use.
• Climbing: each employee uses at least one hand to grasp the ladder when going up or down (1926.1053(b)(21), read this pass). "Three-point contact" is sound guidance, but it is not that clause's text.
• Inspection: ladders are inspected by a competent person for visible defects on a periodic basis and after any occurrence that could affect safe use (1926.1053(b)(15), read this pass). That is not a pre-use inspection duty.
• Nonconductive siderails where the employee or ladder could contact exposed energized equipment (1926.1053(b)(12), read this pass).
• Top step: "The top or top step of a stepladder shall not be used as a step" (1926.1053(b)(13), read this pass). See Fix on platform and step-stool surfaces in How NOT to use it.

General safe-use guidance for everyone (OSHA fact sheet 3660, read this pass, and manufacturer instructions):

• Inspect before every use for defects such as missing rungs, loose bolts, cleats or screws; mark or tag a defective ladder "Do Not Use" and remove it from service rather than improvising a field repair.
• Keep three limbs on the ladder (two hands and one foot, or two feet and one hand), face the ladder, and keep your body inside the side rails without leaning out past them.
• Carry tools in a tool belt or raise them with a hand line, not in the hands.
• Choose a ladder whose load rating covers your weight plus all tools and materials, set it on stable, level footing, and keep access areas clear. The 4:1 rule does not replace securing the ladder against displacement where the site makes displacement possible; lock or guard doors, use both rails at the top support unless an approved single-support attachment is fitted, and never move or extend a ladder while it is occupied.
• Survey the area for overhead power lines before starting.

✦ Matching

• Does, the beginner match: low-force work from a stable, level footing where the user can keep their body between the rails and follow the exact ladder label: interior high-ceiling reach, painting and gutter cleaning at modest height, siding and similar light tasks. Matched first by duty rating against total load and second by height against the setup and landing rules.
• Gated, not beginner matching: electrical fixture and light installation. De-energize and verify electrical equipment before fixture work. Keep ladders and people at least 10 feet from overhead lines (OSHA fact sheet 3660 states 10 feet for ladders and tools, read this pass) unless a qualified electrical-safety plan establishes otherwise. NIOSH, per the review, says unqualified persons should not work on energized parts and should stay at least 10 feet from them [manual, relayed] (NIOSH's electrical page returned no text this pass). Fiberglass reduces conductivity risk but is not complete electrical protection.
• Gated, not beginner matching: roofing-edge access. A ladder is access to a roof, not roof-edge fall protection; it provides no protection once the person steps onto the roof. Roof work on an unprotected edge can require a separate fall-protection system (OSHA 1926.501, not re-read this pass [manual, relayed]). A ladder to the roof and a plan for the roof edge are separate things.
• Gated, not beginner matching: tree work. Tree work adds unstable supports, falling material, cutting forces and task-specific climbing and fall-protection requirements. It requires task-specific equipment, weather limits and training. Not a ladder-matching project.
• Gated: articulating-ladder modes and accessories. Use only modes shown on the exact ladder's label and manual. Before climbing, confirm every hinge and extension lock is visibly and physically seated. In 90-degree mode, follow the manual's wall-contact orientation and never climb the vertical side. Use trestle or scaffold mode only with the required brackets, approved plank, spacing, height and load limits. Use only accessories (stabilizers, standoffs, wall pads, levelers, planks, brackets) approved for the exact ladder model and configuration; material-wide compatibility claims, such as one stabilizer said to fit "across aluminum, wood and fiberglass" ladders, do not establish approval for a given rail profile, length, duty rating or mode. Do not map a generic articulating ladder to scaffold work. [manual, relayed] (Little Giant's operating manual as described by the reviewer; the fetch failed this pass).
• Kit-fit, pairs with: a tool belt or hand line; a pail shelf or tool tray approved for the exact model (the original run's Ladder-Max standoff and Werner's standalone tray are named only as examples of a product category, not as approved for any particular ladder).
• Kit-fit, ladder versus platform, scaffold or lift. Prefer a platform, scaffold or lift when the task requires lateral travel, overreaching, heavy or two-handed force, bulky material, repeated repositioning, long duration, or work whose fall consequence cannot be acceptably controlled from a ladder. This is a consensus heuristic, not a bright-line OSHA threshold; OSHA's construction rules do not generally prohibit working from a portable stepladder (OSHA interpretation letter of 2007-11-28, per the reviewer; not re-read) [manual, relayed]. Short duration does not cure the other hazards.
• Not-for (project-keyed): using a ladder where the work needs overreaching, significant drilling or pulling force, bulky material, or a defeated secure grasp (NIOSH names overreaching, carrying objects and excessive force as recurring causes; the NIOSH ladder page read this pass lists overreaching as improper use); using an aluminum ladder where it or the user could contact overhead lines or exposed energized equipment. Load mismatches (for instance a Type III on heavy work) are a duty-rating problem to avoid; the Type label alone is not a declared violation.
• Access: beginner guidance is the low-force match above plus: check the angle, keep three limbs on the ladder, verify rating against total load, confirm stable level footing, and inspect before each use. Choosing fiberglass, following a 4:1 angle or wearing a harness does not make live electrical work, roof work or arboricultural work beginner-safe.
• Revival: not applicable; the ladder is a live, regulated safety tool.
• Selection sequence: (1) decide whether a ladder is suitable at all, given reach, force, lateral movement, load, duration, weather, electrical exposure and fall consequence; (2) select an approved configuration and sufficient length without standing above the marked highest standing level; (3) check total load against the rating; (4) check footing, top support, displacement controls, access clearance and exact accessory compatibility; (5) inspect locks, hinges, rails, rungs, feet, rope, pulley, labels and contamination; (6) reposition rather than overreach, or move to a safer platform if the task defeats a secure climbing posture.

Anatomy

• Stepladder (A-frame): front and rear rails; steps (flat treads); the spreader or locking brace holding front and back open ("A metal spreader or locking device shall be provided on each stepladder," 1926.1053(a)(8), per the original run); the top cap; the pail shelf (model-dependent); slip-resistant feet.
• Extension ladder: base section (stationary) and fly section (slides to extend); rope-and-pulley; rung locks (dogs or pawls) that must be secured before climbing; slip-resistant feet. Do not assume all extension ladders orient base, fly, rope, locks and shoes identically: follow the labels for fly-section orientation, overlap, highest standing level, lock engagement and climbing side.
• Articulating ladder: several model-specific structures sharing hardware, not a free-form transformer. Each mode changes the load path; hinge locks, rung locks, levelers, wall pads, trestle brackets, planks and standoffs are specific to model and configuration.
• Sourced from Werner's published anatomy reference and a secondary tools page [manual, relayed]. Little Giant's and Louisville's own parts diagrams were not reached.

Variations (living)

• Material, aluminum: light, strong and conductive, the property behind the nonconductive-siderail rule where contact with exposed energized equipment is possible.
• Material, fiberglass: reinforced-plastic rails with reduced conductivity relative to aluminum. It is not electrically insulated under all field conditions: damage, contamination, moisture, labels, coatings, hardware, accessories and clearance all matter. The electrical hierarchy is: de-energize and verify, keep the required approach distance, then choose nonconductive rails as an additional control. Product copy such as "useful for working safely around electricity" is marketing and is not relied on here.
• Material, wood: rare in current production, still governed by its own ANSI standard and separately regulated by OSHA [manual, relayed].
• Duty ratings (ANSI-derived; from OSHA fact sheet 3660, read this pass):

OSHA's fact sheet says Types IA, I, II and III come from Subpart X Appendix A (ANSI 1982 editions), and Type IAA comes from 2009 ANSI guidelines that OSHA labels non-mandatory. The rating is based on the total load (person, tools and materials) and the labeled intended use. A Type name alone does not make a task a violation.

• Step stools: OSHA regulates rung spacing separately for step stools (8 to 12 inches) versus standard ladders (10 to 14) [manual, relayed]. A ladder-type step stool may be designed to be climbed on the top cap as well as all steps.
• Platform and podium ladders: have a designated standing platform and surrounding guard structure that vary by product; read the label.
• Tripod/orchard ladders: splayed legs for uneven ground, originally for orchard work. Roof ladders are not merely extension ladders with a generic hook; safety instructions do not transfer between designs.

Trades

Listed as where the tool shows up, not as beginner matches.

• Painting: the largest non-occupational use in the injury record the original run read; interior stepladder to exterior extension work.
• Electrical (residential/commercial): where the ladder meets the nonconductive-rail rule; a gated trade, not a beginner use (see Matching).
• General building/carpentry and roofing: extension and hook- or wheel-equipped roof ladders for eave and ridge access; wind and wet conditions are a hard go/no-go. Roof-edge work has its own fall-protection plan.
• Window washing: trained on setup angle and securing while carrying equipment.
• Tree work (arboriculture): ladder access layered with harness and lanyard fall protection, distinct from rope-and-saddle canopy techniques; a gated trade.
• Firefighting: the aerial-truck descendant rather than the portable ladder.

Lineage

• John H. Balsley's stepladder patent, read directly. John H. Balsley of Dayton, Ohio, US 34,100, "Improved Step-Ladder," issued January 7, 1862 (read on the patent page this pass), documents an improved self-supporting folding stepladder. Its sole claim is an arrangement: front supports, braces, horizontal rods connecting front and back, back supports, braces and a hinged cross-tie, "arranged, connected, and operating as and for the purpose specified." The patent calls itself an improvement. It does not say the steps replace round rungs, does not compare its steps with round rungs, and does not give a fatigue or slip rationale. It does not establish priority over earlier stepladders, and this entry makes no "founding" or "first" claim. An earlier sourced note says stepladders were in use many years before 1862. He followed with US 99,621, February 8, 1870, not read this pass [manual, relayed].
• Extension ladder's rope-and-pulley mechanism: an incremental chain, not one inventor. No single founding patent was identified; the documented sequence is US 333,784 (John Royds, 1886) [manual, relayed], US 369,084 (J.E. Smith, 1887, described as teaching a clutch lever or rung lock worked by rope and pulley, cited in the original run through a later patent's prior-art list, so the mechanism was not read) [manual, relayed], and US 3,347,340, filed 1966, issued 1967, Werner-assigned, an endless-cable hoist refinement naming both Harold W. Huska and James C. Redman as inventors (the review; not re-read this pass) [manual, relayed]. Earlier patent relationships are described only to the mechanism actually read.
• Multi-position/articulating ladder: Little Giant. The commonly assumed inventor name "Levi Gardner" could not be verified and is dropped. Little Giant's own history, per the reviewer's reading, confirms that Hal Wing met a German inventor with a prototype in the early 1970s; the page does not name Walter Kümmerlin or document a licence, so neither is asserted here [manual, relayed]. The company dates itself to 1972 (original run). US 4,407,045 (filed 1981, published 1983) names Leland H. Boothe as inventor and an individual as original assignee, with Little Giant a current assignee, so the assignment chronology is unresolved; it also says combination step/extension ladders were long known. It is evidence of a Little Giant-associated hinge and locking improvement, not the origin of articulating ladders as a family [manual, relayed]. The continuation US 4,566,150A is not re-read.
• General ancestors: flexible pole and rope ladders, predating any rigid self-supporting form by millennia (see Proof of existence). Contemporaries: scaffolding and mobile work platforms, an adjacent category, not researched in depth here.
• A scaled descendant: the aerial fire-ladder truck (see History).

History

• No flat-step story. The original run's claim that Balsley replaced round rungs with flat steps as a fatigue or slip fix is withdrawn: the patent does not say it (see Lineage). This entry no longer carries it as a form-follows-failure case.
• The aerial fire-ladder truck. The Smithsonian's Hayes Fire Truck plate identifies Daniel D. Hayes and William Free, US 74,821, issued February 25, 1868, and calls it the first fire-truck aerial ladder (the reviewer's reading of the museum record; not re-read this pass) [manual, relayed]. The original run's details (a 50-foot wooden spring-assisted ladder, a sale to what became American LaFrance in 1884, a machinist at the San Francisco Fire Department shop) need their own cited records and are unresolved here; an SFFD museum history describes a crank/worm mechanism in service, so different production versions and drive systems should not be merged. The documented failure it addressed, earlier hook-and-ladder attempts being unstable, is from the original run and is not re-sourced.
• Fiberglass adoption near electrical work. The original run cited a "CDC figure" that 91% of ladder-related electrocution deaths involved metal ladders contacting overhead lines, with about 17 of about 300 annual deaths from electrocution. The review says no matching annual death count above 300 is established, and that figure is withdrawn; the 91% is carried only as unverified [manual, relayed]. What the regulation supports: OSHA requires nonconductive siderails where the employee or ladder could contact exposed energized equipment (1926.1053(b)(12), read this pass), which is a material-selection control, not permission for energized work. No single named trigger incident was found behind the fiberglass standard.

Human side

• Trades and how use differs. Window washers are trained on extension-ladder angle-and-securing technique while carrying equipment; painters and general contractors use stepladders and platforms for interior work and extension ladders outside; roofers commonly use a second, hook- or wheel-equipped ladder for on-roof work and treat wind and wet as a go/no-go factor; arborists layer harness and lanyard systems on top of ladder access; firefighters use the aerial-truck descendant for structure fires. [manual, relayed] from the original run. These are descriptions of trade practice, not instructions: electrical, roof and tree work are gated in Matching.
• Named makers. Werner Ladder Co. (founded 1922; aluminum climbing products from 1950; over 600 patents), Louisville Ladder (founded 1946 by Henry Kuempel Sr.; 30+ patents) and Little Giant Ladder Systems (Wing Enterprises, founded 1972 by Hal Wing; its founding prototype source is described under Lineage without a name) [manual, relayed].
• Anecdotal forum texture, unverified. Mike Holt's Forum, thread "Lessons learned," started 2004-09-06 by user silverromex (forums.mikeholt.com/threads/lessons-learned.3959), carries first-person posts: an extension ladder that kicked out on a painted concrete floor about ten feet up (the poster now ties off or blocks the base); a moderator citing 29 CFR 1910.25 securing and noting a claimed loophole for fiberglass ladders; two electricians shocked at 277 V while standing on the top step of a 6-ft ladder, one of whom credits being thrown from the ladder for surviving; a hole-hog drill kickback knocking a worker backward off a 16-ft ladder into an excavation. These are unverified personal accounts, not safety-body records, and the "loophole" claim is not endorsed here. Their lesson is the gate in Matching: electrical work from a ladder is not a beginner activity and a ladder's top step is not a standing surface.
• Folklore, honestly flagged. "Walking under a ladder is bad luck" is traditionally traced to Egyptian, Christian and 17th-century gallows associations, plus a plain practical explanation (something could be dropped). These origin stories are repeated, not verified.

Proof of existence

• Stepladder patent: US 34,100, John H. Balsley, issued January 7, 1862, "Improved Step-Ladder" (read this pass). It documents an improved folding stepladder arrangement; it is not claimed here as the first or founding patent.
• Extension-ladder mechanism chain: US 333,784 (Royds, 1886), US 369,084 (Smith, 1887), US 3,347,340 (Huska and Redman, Werner-assigned, filed 1966, issued 1967), an incremental sequence [manual, relayed].
• Multi-position ladder patents: US 4,407,045 (Boothe, inventor; filed 1981, published 1983) and US 4,566,150A, assignment chronology unresolved [manual, relayed].
• Pre-modern ancestor: rock art at the Cuevas de la Araña (Spider Caves), Bicorp, Valencia, Spain, depicts a figure climbing a flexible, bound-material ladder to a beehive, with dating not fully settled (most commonly about 8,000 years), a flexible ancestor, not a rigid ladder [manual, relayed].
• Ancient Egyptian evidence: ladders and wheeled ladder-derived siege towers in Middle Kingdom and New Kingdom siege scenes (Deir el-Bahri, Intef's chapel, the Siege of Dapur reliefs): military ladders, not tradesperson tools [manual, relayed]. No Roman siege-ladder material was located.
• Fire-truck aerial ladder: Hayes and Free, US 74,821, February 25, 1868, per the Smithsonian's Hayes Fire Truck plate [manual, relayed].
• Museum records: the Smithsonian American Art Museum holds a dated "Extension Ladder" (1878) and "Four Step Library Ladder" (Daniel Jackson, 1965), art-collection objects rather than earliest-known examples. A Science Museum Group (UK) search did not surface a ladder object record in the original run (a result of that search, not proof of absence).

References

• {title: "US34,100A — Improved Step-Ladder", author: "John H. Balsley", url: "patents.google.com/patent/US34100A/en", kind: patent}
• {title: "US99,621A — Improvement in Step-Ladder", author: "John H. Balsley", url: "Google Patents", kind: patent}
• {title: "US333,784A — Extension Ladder", author: "John Royds", url: "Google Patents", kind: patent}
• {title: "US369,084A", author: "J.E. Smith", url: "Google Patents (cited as prior art in US5582270A)", kind: patent}
• {title: "US3,347,340A — Extension Ladders", author: "Harold W. Huska and James C. Redman", url: "patents.google.com/patent/US3347340A/en", kind: patent}
• {title: "US4,407,045A — Ladder Hinge and Multi-Position Locking Mechanism", author: "Leland H. Boothe (inventor)", url: "patents.google.com/patent/US4407045A", kind: patent}
• {title: "US4,566,150A", author: "Wing Enterprises", url: "Google Patents", kind: patent}
• {title: "Wikipedia — John H. Balsley", url: "en.wikipedia.org/wiki/John_H._Balsley", kind: named_maker}
• {title: "Little Giant Ladder Systems — 'Our Story'", url: "littlegiantladders.com/pages/our-story", kind: named_maker}
• {title: "Little Giant — Articulated Extendable Ladder Operating Manual", url: "cdn.littlegiantladders.com (manual, model-specific)", kind: named_maker}
• {title: "Deseret News — Hal Wing obituary (2012) and retrospective (2022)", url: "deseret.com", kind: named_maker}
• {title: "WernerCo — 'Werner Celebrates 100 Years of Innovation' (2022)", url: "wernerco.com", kind: named_maker}
• {title: "Werner — Fiberglass Ladder Technical Manual", url: "wernerco.com/docs/default-source/literature/gm6070-fg-techmanual.pdf", kind: named_maker}
• {title: "Louisville Ladder — Company page", url: "louisvilleladder.com/company", kind: named_maker}
• {title: "FireRescue1 — 'The man behind firefighting's first aerial truck'", url: "firerescue1.com", kind: named_maker}
• {title: "Smithsonian National Museum of American History — Hayes Fire Truck Engine Plate", url: "americanhistory.si.edu/collections/object/nmah_1347148", kind: museum}
• {title: "Seattle Times archive — 'Electricians shouldn't use aluminum ladders'", url: "archive.seattletimes.com", kind: reference}
• {title: "OSHA 29 CFR 1926.1053 — Ladders", url: "osha.gov/laws-regs/regulations/standardnumber/1926/1926.1053", kind: reference}
• {title: "OSHA 29 CFR 1926.1060 — Training Requirements", url: "osha.gov/laws-regs/regulations/standardnumber/1926/1926.1060", kind: reference}
• {title: "OSHA 29 CFR 1926.501 — Duty to Have Fall Protection", url: "osha.gov/laws-regs/regulations/standardnumber/1926/1926.501", kind: reference}
• {title: "OSHA — Am I Covered by OSHA?", url: "osha.gov/node/59586", kind: reference}
• {title: "OSHA3660 Fact Sheet — Reducing Falls in Construction: Safe Use of Extension Ladders", url: "osha.gov/sites/default/files/publications/OSHA3660.pdf", kind: reference}
• {title: "OSHA interpretation — Working from a Portable Stepladder (2007-11-28)", url: "osha.gov/laws-regs/standardinterpretations/2007-11-28", kind: reference}
• {title: "OSHA interpretation — Using a Stepladder as a Non-Self-Supporting Ladder (2010-01-21)", url: "osha.gov/laws-regs/standardinterpretations/2010-01-21", kind: reference}
• {title: "OSHA eTool — Construction: Falls — Ladder Safety", url: "osha.gov/etools/construction/falls/ladder-safety", kind: reference}
• {title: "NIOSH — Ladder Safety", url: "cdc.gov/niosh/falls/ladder/index.html", kind: reference}
• {title: "NIOSH — Electrical Safety in the Workplace", url: "cdc.gov/niosh/electrical-safety/index.html", kind: reference}
• {title: "CDC MMWR — 'Occupational Ladder Fall Injuries — United States, 2011'", url: "cdc.gov/mmwr/preview/mmwrhtml/mm6316a2.htm", kind: reference}
• {title: "Ladder-Related Injuries Treated in U.S. Emergency Departments, 1990–2005", site: "PubMed", url: "pubmed.ncbi.nlm.nih.gov/17478268", kind: reference}
• {title: "NIOSH — A Story of Impact: Ladder Safety App (2013 all-settings estimate)", url: "cdc.gov/niosh/docs/2015-176/pdfs/2015-176.pdf", kind: reference}
• {title: "NIOSH FACE Reports 93NJ062, 2003-08, 2003-11 (search-summary sourced, not directly fetched)", url: "stacks.cdc.gov", kind: reference}
• {title: "Werner Parts — 'Know Your Werner Ladder: Basic Ladder Terminology'", url: "wernerparts.com/pages/ladder-anatomy", kind: named_maker}
• {title: "American Ladder Institute — A14.7 standard page", url: "americanladderinstitute.org/page/A147Standard", kind: reference}
• {title: "OSHA SHIB092719 — Working Safely with Mobile Ladder Stands", url: "osha.gov/sites/default/files/publications/SHIB092719.pdf", kind: reference}
• {title: "Mike Holt's Forum — 'Lessons learned', started 2004-09-06 (anecdotal)", url: "forums.mikeholt.com/threads/lessons-learned.3959", kind: forum}
• {title: "ContractorTalk.com — 'Fell off my ladder today' (search-summary sourced, anecdotal)", url: "contractortalk.com/threads/fell-off-my-ladder-today.23905", kind: forum}
• {title: "HowStuffWorks — 'Why Is Walking Under a Ladder Unlucky?'", url: "people.howstuffworks.com", kind: reference}
• {title: "Cuevas de la Araña rock art — multiple sources (Ancient Origins, The History Blog, Wikipedia)", url: "various", kind: archaeological}
• {title: "Siege of Dapur / Egyptian siege-scene sources", url: "en.wikipedia.org/wiki/Siege_of_Dapur; researchgate.net", kind: archaeological}
• {title: "Smithsonian American Art Museum — 'Extension Ladder' (1878) and 'Four Step Library Ladder' (1965)", url: "americanart.si.edu", kind: museum}
• {title: "Little Giant Velocity — product page (marketing; not relied on for safety claims)", url: "littlegiantladders.com/products/velocity-articulating-ladder", kind: named_maker}
• {title: "GutterBrush — Ladder-Max Standoff Stabilizer (product category example only; model-specific approval required)", url: "gutterbrush.com/products/ladder-max-standoff-stabilizer", kind: named_maker}

The reviewer's corrections (8)

• BLOCKER — 1. Remove electrical, roof, and tree work from generic beginner matching — Exact claim: The ladder “provides brief elevated reach for … electrical fixture and light install … roofing-edge access, tree work,” while fiberglass is “the standard choice near electrical work” and current product copy is summarized as useful for “working safely around electricity.”
• BLOCKER — 2. Make articulating modes and accessories model-specific — Exact claim: A multi-position ladder generically “reconfigures between A-frame, straight-extension, stairwell/trestle, and 90° scaffold-base forms,” and it pairs with a stabilizer/standoff said to be compatible “across aluminum, wood, and fiberglass extension and articulating ladders.”
• SHOULD-FIX — 3. Separate OSHA law from general consumer guidance and correct the quoted provisions — Exact claim: Beginner guidance is “code-anchored”; “Keep 3-point contact: at least one hand on the ladder at all times while climbing (1926.1053(b)(21))”; inspection before every use is described as “a competent-person visual check … (1926.1053(b)(15)–(16))”; the 3-foot extension is stated without its …
• SHOULD-FIX — 4. Correct the Balsley patent and remove the unsupported “founding” claim — Exact claim: “Founding U.S. patent for the self-supporting stepladder,” and Balsley's “real contribution” was “replacing round rungs with flat steps,” described as a direct safety response to fatigue and slipping.
• SHOULD-FIX — 5. Reconcile platform, step-stool, and top-step rules by product design — Exact claim: “The top or top step of a stepladder shall not be used as a step,” alongside “A platform ladder is a stepladder with a standing platform instead of a top step” and a general prohibition on the top step or top cap.
• SHOULD-FIX — 6. Repair the injury statistics and preserve their denominators — Exact claim: “over 500,000 ladder-related injuries treated annually in the U.S., roughly 164,000 of them emergency-room visits, and more than 300 deaths a year … with 97% of ladder-related ER visits non-occupational.”
• MINOR — 7. Tighten the “ladder versus scaffold/lift” matching boundary — Exact claim: A ladder is “for climbing to and briefly working at a point, not for sustained overhead work,” and scaffolds/lifts “take over once work is sustained, extends across a wide area, or requires both hands free for an extended period.”
• MINOR — 8. Bound the multi-position and aerial-ladder history claims — Exact claim: Walter Kümmerlin is named as the German prototype inventor; the Little Giant patents are described as company-assigned evidence consistent with sales a decade before patenting; and the Hayes truck is described as a 50-foot spring-assisted design sold to what became American LaFrance in 1884.