Construction safety training captions: OSHA 1926, OSHA 10/30-hour training, Focus Four hazards, and WCAG 2.1 AA

OSHA 10/30-hour construction training: structure, delivery, and video content

The OSHA Outreach Training Program

The OSHA Outreach Training Program is OSHA's primary mechanism for delivering broad-based construction safety awareness training to the construction workforce. The Program is administered through OSHA-authorised trainers who have completed OSHA trainer courses (the 500-level courses for construction: OSHA #500 Trainer Course in Occupational Safety and Health Standards for the Construction Industry, and #501 for general industry). Authorised trainers deliver the 10-hour and 30-hour construction courses to workers and supervisors. Upon completion, participants receive an OSHA Outreach Training Program card — the "OSHA 10 card" or "OSHA 30 card" — that many construction contractors, project owners, and unions require as a condition of site access or employment.

The OSHA 10-hour course covers construction hazard awareness at the introductory level, with required topics including the Focus Four hazards (falls, struck-by, electrical, caught-in/between) and elective topics from a defined list of additional hazard categories. The OSHA 30-hour course covers a broader and more detailed curriculum suitable for supervisors, foremen, and safety personnel, with required topics and a larger elective component. Both courses may be delivered entirely in-person (trainer-led instruction), in a hybrid format (video modules for content delivery, in-person for discussion and hands-on elements), or — where permitted — through OSHA-authorised online delivery formats. The online and hybrid delivery formats are primarily video-based: pre-recorded instructional modules that deliver the regulatory content, which participants watch before or between trainer-led sessions.

These video modules are where the captioning obligation is most acute. An in-person trainer-led session has real-time accommodation options (ASL interpreter, real-time captioning). A pre-recorded video module for an OSHA 10 online course does not — the hearing-impaired construction worker taking the OSHA 10 course online depends entirely on the caption track of each video module. If the caption track of the fall protection module mis-transcribes "Personal Fall Arrest System" as "personal fall arrest system" (inconsistent capitalisation that loses the technical term's proper-noun status), mis-transcribes "29 CFR 1926.502" as "29 CFR 1926-502" (hyphen instead of decimal), or renders "swing radius" as "swing radio" (phonetic false match), the caption track is not accurately conveying the OSHA regulatory content that the training is required to teach.

Employer-administered construction safety training video

Beyond the OSHA Outreach Training Program, construction employers administer their own safety training programmes that satisfy specific OSHA 1926 subpart training requirements: fall protection training per 29 CFR 1926.503, scaffolding training per 29 CFR 1926.454, excavation competent-person training per 29 CFR 1926.651, crane operator certification and training per 29 CFR 1926.1427 and 1926.1430, and confined space training per 29 CFR 1926.1209. These employer-administered programmes typically combine video-based instructional content (which delivers the regulatory background, OSHA standards references, and hazard identification framework) with hands-on demonstration and practical evaluation. The video component of employer-administered construction safety training is the component that must be captioned for hearing-impaired employees — hands-on demonstration and practical evaluation can be accommodated through other means, but the instructional video content that delivers regulatory vocabulary, OSHA citation references, and safety procedure descriptions requires an accurate caption track.

The vocabulary challenge in employer-administered construction safety training video is compounded by site-specific overlay: in addition to the shared OSHA 1926 vocabulary, employer training videos reference specific equipment models (crane manufacturer model names and load chart designations), site-specific area names ("the north excavation" at a specific project site), subcontractor names, and employer-specific safety management system vocabulary (specific permit formats, site-specific hazard communication identifiers). A general contractor's site-specific safety orientation video that references specific site areas, specific equipment, and specific subcontractor safety responsibilities is even less likely to be accurately captioned by generic STT than a generic OSHA 10 module — both the shared regulatory vocabulary and the site-specific overlay are outside generic STT training data.

Construction safety training content types by hazard category

Fall protection — 29 CFR 1926.502 and Subpart M

Falls are the leading cause of fatalities in construction — approximately 36–40% of annual construction fatalities in the US are fall-related. OSHA's fall protection standards at 29 CFR 1926 Subpart M (§§ 1926.500–1926.503) require fall protection systems for work at heights of 6 feet or more, and require documented training on fall protection per 29 CFR 1926.503. Fall protection training video covers: the triggers for fall protection requirement (leading edges, open-sided floors, excavations, unprotected sides and edges, wall openings, roofing work); the three categories of fall protection (fall arrest, fall restraint, and fall prevention systems); Personal Fall Arrest System (PFAS) equipment components (harness, lanyard, anchorage, connector, deceleration device); Self-Retracting Lifeline (SRL) selection and inspection; anchorage point requirements (5,000-pound capacity per attached employee per 29 CFR 1926.502(d)(15)); tie-off procedures and D-ring positioning; swing-fall hazard geometry; and fall protection plan requirements for leading-edge work where conventional fall protection is infeasible.

The vocabulary challenge in fall protection training has a distinctive collision risk. PFAS — Personal Fall Arrest System — shares its acronym with PFAS — Per/Polyfluoroalkyl Substances, the class of chemical contaminants sometimes called "forever chemicals." In OSHA 1926 fall protection training, "PFAS" always means Personal Fall Arrest System; in HazCom or environmental contamination training, "PFAS" means the chemical category. A learner who encounters "PFAS" in fall protection training captions without the audio context may be uncertain which PFAS is being referenced — and a generic STT system has no context to preferentially render the fall protection meaning over the chemical meaning. The GlossCap glossary layer resolves this by context-weighting the construction safety vocabulary domain when applied to fall protection training video.

• PFAS (Personal Fall Arrest System): narrated as "P-F-A-S" (four letters) or "pee-fas" (two syllables). STT variants: "PFAS" (correct in fall protection context), "P.F.A.S." (with periods), "pfas" (lowercase). Note collision with chemical contamination acronym — consistent capitalisation and domain-correct rendering required.
• SRL (Self-Retracting Lifeline): narrated as "S-R-L" (three letters) or "the SRL." STT variants: "SRL" (correct), "S-R-L" (hyphenated), "scrolled" (phonetic false match — "S-R-L" sounds like "es-ar-el" at speed, and "scrolled" is a high-frequency past-tense verb), "S.R.L." (with periods). In a video demonstrating SRL inspection procedures, "attach the scrolled to the anchorage point" is not instructionally recoverable for a hearing-impaired learner.
• Anchorage / D-ring: "anchorage" in OSHA 1926 fall protection context has a specific technical meaning (a secure point of attachment to a structure) distinct from the common English meaning (a place where ships anchor). STT handles "anchorage" correctly as a word but may inconsistently capitalise it when used as a technical term vs a common noun. "D-ring" — the D-shaped metal connector on a harness or anchor — is rendered by STT as "D ring" (without hyphen), "de ring," "dee ring," or "D-ring" (correct) inconsistently.
• Swing radius / swing-fall: "Swing radius" in fall protection refers to the horizontal distance a worker can travel through the air if they fall from an offset anchor point, resulting in a pendulum-swing hazard. STT: "swing radius" (correct), "swing radio" (phonetic false match — "radius" and "radio" are close enough in fast narration for STT to substitute the higher-frequency word), "swing ray-dee-us" (phonetic rendering without the collapsed form). In fall protection training, the swing radius calculation determines safe anchor positioning — "swing radio" in a caption obscures a quantitative safety concept.
• 29 CFR 1926.502 citations: narrated as "twenty-nine C-F-R nineteen-twenty-six dot five-oh-two" at varying speeds. STT variant forms: "29 CFR 1926.502" (correct), "29 C.F.R. 1926.502" (with periods on CFR), "29 CFR 1926-502" (hyphen instead of decimal — a common STT artefact for decimal citations), "twenty-nine CFR nineteen twenty-six point five oh two" (all words, no numerals), "29 CFR § 1926.502" (with section symbol). Consistent regulatory citation format is required for fall protection training that references specific OSHA standard provisions.

Excavation and trenching — 29 CFR 1926.650–652 (Subpart P)

Excavation and trenching fatalities — primarily trench collapses — are among the most preventable fatal accidents in construction. OSHA's excavation standards at 29 CFR 1926 Subpart P (§§ 1926.650–1926.652) require protective systems for excavations deeper than 5 feet (or shallower if there is a hazard of cave-in), require that a competent person classify soil before workers enter, and establish the standards for sloping, benching, shoring, and trench box systems as protective alternatives. Excavation training video covers: the OSHA definition of "excavation" vs "trench" (an excavation is any man-made cut, cavity, or trench in the earth; a trench is an excavation that is deeper than it is wide, up to 15 feet wide — training must communicate this specific definitional distinction); soil classification (Type A soil — cohesive soils with unconfined compressive strength of 1.5 tons per square foot or greater, in which sloping at 3/4:1 is permitted; Type B soil — cohesive soils with lower strength plus other characteristics; Type C soil — granular soils or soils subject to fissuring, requiring 1½:1 sloping); the four protective system options (sloping/benching, trench boxes/shields, shoring systems, and other structural raker systems); and the competent-person obligation for daily inspections and after any hazard-triggering event (rain, freeze-thaw, surface load changes).

• Subpart P: narrated as "Subpart P" or "sub-part pee" (the letter P, not the word "pee"). STT variants: "Subpart P" (correct), "sub part P" (without hyphen), "sub-part pee" (phonetic — the letter sounds like the word for urination, creating a potentially comic caption rendering that is also contextually incorrect), "sub part p" (lowercase letter). In a narration that references multiple subparts — "Subpart M for fall protection, Subpart P for excavation, Subpart CC for cranes" — consistent subpart letter rendering is necessary for regulatory reference accuracy.
• Soil classification (Type A/B/C): "Type A," "Type B," "Type C" soil classifications are narrated as ordinal identifiers. STT generally handles "Type A" well, but in fast narration "Type A soil" → "type-A soil" or "Type A, soil" (with spurious comma), and the full soil classification sentence "Type A soil with an unconfined compressive strength of at least one-point-five tons per square foot" has multiple measurement vocabulary components that STT renders inconsistently ("one-point-five," "1.5," "one point five" — inconsistent numeral/word rendering across occurrences in the same video).
• Competent person (soil classification): in Subpart P, "competent person" is used in the OSHA-defined sense — a person designated by the employer who has been trained to identify hazardous or unsatisfactory soil conditions. The competent person for excavation is not the same role as the competent person for fall protection or scaffolding; each OSHA standard that uses the term specifies the training and knowledge required for the role in that context. Generic STT renders "competent person" as "competent person" (correct) or "competent persons" (plural when singular was narrated), but the more important failure is collapsing "competent person" and "qualified person" — see the detailed vocabulary section below.

Cranes and derricks — 29 CFR 1926.1400 (Subpart CC)

Crane and derrick operations in construction are governed by OSHA's most complex construction standard: 29 CFR 1926 Subpart CC (§§ 1926.1400–1926.1442), which covers equipment, operator certification, rigger qualification, signal-person qualification, assembly/disassembly, inspection, operational requirements, and ground conditions. Crane training video covers: operator certification requirements under 29 CFR 1926.1427 (third-party accredited program, employer-issued documentation); the four defined personnel roles — operator (certification required), signal person (qualification required), rigger (qualified or competent), and lift director (for complex lifts); load chart reading and interpretation; rigging vocabulary (sling types, hitches, rigging angle factors, sling angle); at-two-block (A2B) protection systems; ground conditions assessment; assembly and disassembly director requirements; critical lifts and pre-lift meetings; power line safety and the 20-foot radius rule under 29 CFR 1926.1408; and the OSHA-defined distinctions between the crane operator role, the signal person role, the rigger role, and the lift director role.

Crane and rigging vocabulary is among the most specialised in construction safety training — it requires detailed knowledge of crane design (boom, jib, luffing jib, lattice boom, telescoping boom), rigging hardware (shackles, hooks, wire rope, synthetic slings, chain slings, beam clamps, below-the-hook lifting devices), load calculation methodology, and the specific OSHA-defined personnel qualification standards. This vocabulary is almost entirely absent from general STT training data.

• A2B (at-two-block): at-two-block is a hazardous condition in which the load block (or hook block) contacts the boom tip or upper block, potentially causing the crane to fail catastrophically. "A2B" narrated as "A-two-B" or "ay-two-bee." STT: "A2B" (correct), "a to b" (phonetic — a directional phrase meaning "from A to B"), "A 2 B" (space-separated), "a2b" (lowercase). In crane training, "the A2B protection system prevents the load block from contacting the boom tip" — rendered as "the a to b protection system" — converts a specific technical crane hazard designation into a directionality phrase that communicates nothing about the hazard.
• Signal person / qualified rigger / competent rigger / lift director: four distinct OSHA-defined roles under Subpart CC. STT renders all four correctly as multi-word phrases but does not consistently capitalise them when used as OSHA terms of art vs common English descriptions. More critically, generic STT may render "qualified rigger" and "competent rigger" interchangeably — and these are not interchangeable: OSHA's Subpart CC uses both "qualified rigger" (the standard for rigging under 1926.1425) and "competent person" (for other Subpart CC functions including ground conditions assessment) as defined terms with specific training criteria.
• Swing radius (crane): in crane operations, swing radius refers to the arc of the rotating crane superstructure — the area that a rotating crane occupies during operation. "Swing radius" in fall protection means something different (the pendulum arc of a falling worker). In crane training, "swing radius" must be transcribed accurately and distinguished from the fall protection usage — a general-purpose STT system has no mechanism to apply context-specific rendering to a term used in two different OSHA 1926 contexts with two different technical meanings.
• Travel path: the route a crane travels while moving on a construction site. STT: "travel path" (correct), "travel-path" (hyphenated), "travel pad" (phonetic false match — "path" → "pad" in fast speech). In crane assembly/disassembly training, "establish a clear travel path for the crane" becomes "establish a clear travel pad for the crane" — meaningless to a hearing-impaired learner reading the caption.

Scaffolding — 29 CFR 1926.451–452 (Subpart L)

Scaffolding standards at 29 CFR 1926 Subpart L (§§ 1926.450–1926.454) govern scaffold design, erection, inspection, use, and dismantling for all supported and suspended scaffold types used in construction. Scaffolding training video covers: scaffold types (frame/fabricated, tube-and-coupler, systems scaffolding/modular, mast-climbing, and the various suspended scaffold types including two-point/swinging, multi-point, catenary, float, needle beam, outrigger, ladder jack, window jack, and boatswain's chair); the competent person for scaffolding (erected, modified, and dismantled under the direction of a qualified person; inspected before each work shift and after any occurrence that could affect structural integrity by a competent person); the three-way fall protection obligation at 10 feet for scaffold work (guardrail, personal fall arrest, or both); and the scaffold loading requirements including rated capacity and the 4:1 safety factor for supported scaffolds.

• Tube-and-coupler: a traditional scaffold system using individual steel tubes connected by right-angle, swivel, and sleeve couplers. "Tube-and-coupler" narrated with the hyphenated compound form. STT: "tube and coupler" (without hyphens — common), "tube-and-coupler" (correct), "tube uncoupler" (mishearing — inverting the conjunction to a prefix that reverses the meaning). In a training video comparing scaffold systems, "tube-and-coupler scaffolding requires a competent person to design the layout" — rendered as "tube uncoupler scaffolding" — creates confusion about a scaffold type designation.
• Mast-climbing / mast-climbing work platform: a scaffold type that uses a motorised unit that climbs a vertical mast, used for facade work on high-rise buildings. "Mast-climbing" narrated as "mast climbing" (two words) or "mast-climbing" (hyphenated). STT: "mast climbing" (correct two-word form), "mast-climbing" (hyphenated, correct), "mass climbing" (phonetic false match — "mast" → "mass" in fast speech with dental fricative elision).
• Boatswain's chair: a single-point suspended scaffold for individual worker support. Narrated as "BOSE-un's chair" (the standard nautical pronunciation). STT: "boatswain's chair" (correct), "bosun's chair" (common maritime abbreviation — equally correct), "bosen's chair" or "Bose and chair" (phonetic false matches on the unusual phonemic sequence of "boatswain"). In suspended scaffold training that references the boatswain's chair as a scaffold type, "Bose and chair" in a caption renders a recognised scaffold type as a brand-name speaker and furniture conjunction.

Electrical safety — NFPA 70E and lockout/tagout

Electrical safety training for construction workers covers: OSHA 1926 Subpart K electrical standards (§§ 1926.400–1926.449) for construction-site electrical work; NFPA 70E (the Standard for Electrical Safety in the Workplace) as the supplementary standard for arc flash hazard assessment and PPE selection that is referenced in many construction employer electrical safety programmes; lockout/tagout (LOTO) under 29 CFR 1926.417 for construction (and 29 CFR 1910.147 for general industry, which applies to construction activities performed in industrial facilities); and ground fault protection requirements. Arc flash training — covering the thermal energy released during an arc flash event, expressed as incident energy in calories per centimetre squared (cal/cm²), and the PPE Category system (PPE Category 1/2/3/4) for PPE selection based on incident energy exposure — is the most vocabulary-dense electrical safety training content type in construction.

• NFPA 70E: National Fire Protection Association 70E. Narrated as "N-F-P-A seventy-E" or "NFPA seventy-E." STT: "NFPA 70E" (correct), "NFPA 70-E" (hyphenated — common variant), "N.F.P.A. seventy E" (with periods and space), "NFPA seventy-e" (lowercase letter suffix). "NFPA" without context → STT also renders "nfpa" (lowercase) or "N.F.P.A." (with periods), neither of which is consistent with the standard designation format used in training documentation.
• Arc-rated (AR) / arc flash: "arc-rated" is the PPE designation for clothing tested to a specific ATPV (Arc Thermal Performance Value) rating expressed in cal/cm². "Arc flash" is the electrical discharge event. STT: "arc-rated" (correct) or "arc rated" (without hyphen — common), "arc flash" (correct). "ATPV" — "A-T-P-V" (four letters) — STT: "ATPV" (correct), "A T P V" (letter-spaced), "ATV" (three letters — missing the P — a very common abbreviation for all-terrain vehicle, creating a false match in an electrical safety context).
• cal/cm² (calories per centimetre squared): the unit for incident energy in arc flash analysis. Narrated as "cal per centimeter squared," "cal-per-centimeter-squared," or "cal-cm-squared." STT variants: "cal/cm²" (correct symbol form — rarely produced by STT), "cal per centimeter squared" (verbose word form — correct), "cal-cm-squared" (abbreviated word form — correct), "cal per CM squared" (inconsistent CM capitalisation), "kal per centimeter squared" (phonetic variant on "cal"). Consistent rendering of the incident energy unit is required across a 45-minute arc flash training course that references the cal/cm² threshold multiple times when discussing PPE category selection.
• PPE Category 1/2/3/4: the NFPA 70E arc flash PPE categories (replacing the older PPE level designations in the 2012 and later editions of NFPA 70E). Narrated as "PPE Category one" through "PPE Category four." STT: "PPE Category 1" through "4" (correct), or "PPE category one" (correct lowercase word form), but inconsistency in numeral vs word form across a single video creates caption variability that is confusing for learners. "PPE" itself → "P-P-E" (correct), "ppe" (lowercase), "P.P.E." (with periods), or in very fast speech "peepee" (phonetic — the doubling of the P sound at speed).
• Lockout/tagout (LOTO): narrated as "lockout-tagout" or "LOTO." STT: "lockout/tagout" (correct slash form), "lockout-tagout" (hyphenated — common), "lock out tag out" (space-separated — each element as separate word), "LOTO" (correct), "lotto" (phonetic false match — the lottery game, creating a distinctly incongruous caption in the context of electrical energy control procedures).

Confined space entry — 29 CFR 1926.1200 (Subpart AA)

OSHA's construction confined space standard at 29 CFR 1926 Subpart AA (§§ 1926.1200–1926.1213) governs permit-required confined space entry in construction. (Note: the construction confined space standard is Subpart AA, distinct from the general industry confined space standard at 29 CFR 1910.146, which applies in manufacturing and other general industry settings.) Construction confined spaces include trenches, excavations, utility vaults, tanks, manholes, tunnels, and any other enclosed or partially enclosed space that workers must enter to perform construction work. Confined space training video covers: the definition of a confined space (limited means of entry or exit, not designed for continuous human occupancy) and the three-part test for permit-required confined space status (contains or has potential to contain a serious atmospheric hazard; contains material that could engulf an entrant; has an internal configuration that could trap or asphyxiate; or contains any other recognised serious safety or health hazard); atmospheric monitoring requirements and action levels for oxygen (O2 deficiency below 19.5%, O2 enrichment above 23.5%), flammable gas (LEL trigger for evacuation), and toxic contaminants (IDLH threshold); the three roles in permit-required confined space entry (authorised entrant, attendant, entry supervisor); permit system requirements; rescue plan and emergency services coordination; and the host employer/controlling contractor/entry employer coordination requirements specific to the construction standard.

• IDLH (Immediately Dangerous to Life and Health): the NIOSH/OSHA threshold above which immediate or delayed permanent adverse health effects or death may result from a 30-minute exposure. Narrated as "I-D-L-H" (four letters) or "IDLH" (as a word — "idle-H" or "ID-el-H"). STT variants: "IDLH" (correct), "I D L H" (letter-spaced), "idle H" (phonetic — "idle" is a high-frequency English adjective, and "idle H" is a plausible-looking but meaningless combination in caption context), "I.D.L.H." (with periods). In confined space training, the IDLH threshold defines the point at which non-entry rescue is required — "the IDLH for carbon monoxide is 1,200 ppm" rendered as "the idle H for carbon monoxide is 1,200 ppm" communicates nothing about the safety standard being cited.
• LEL (Lower Explosive Limit): the minimum concentration of flammable gas or vapour in air at which the mixture can ignite. Narrated as "L-E-L" (three letters) or "el-ee-el." STT variants: "LEL" (correct), "L E L" (letter-spaced), "lil" (phonetic — the casual English word for "little," common in informal speech and therefore available as a false-match target for "el-ee-el" in fast narration), "LELL" (doubled final letter). In confined space atmospheric monitoring training, "evacuate immediately if flammable gas reaches 10 percent of LEL" rendered as "evacuate immediately if flammable gas reaches 10 percent of lil" is not instructionally recoverable.
• O2 deficiency / O2 enrichment: oxygen-deficient atmosphere (below 19.5% O2) and oxygen-enriched atmosphere (above 23.5% O2). "O2" narrated as "O-two" or "oxygen two." STT: "O2" (correct symbol form), "O-2" (hyphenated), "oh-two" (phonetic — "oh" is the letter O as a word, which STT may conflate with the exclamation "oh"), "oxygen" (expanding the abbreviation). Consistent "O2" or consistent "oxygen" across a confined space training video is acceptable; inconsistent switching between both forms within the same course is a caption quality problem.
• Authorised entrant / attendant / entry supervisor: the three defined roles in permit-required confined space entry under 29 CFR 1926.1209 (and 29 CFR 1910.146 for general industry). STT handles all three correctly as multi-word phrases but may render "authorised" with the British spelling when the US spelling "authorized" was narrated, or vice versa, depending on the language model's variant preferences. More significantly, "entry supervisor" in the OSHA confined space context has a specific role definition — the person responsible for determining that entry conditions are acceptable — distinct from the general construction management use of "supervisor." Generic STT does not carry this contextual distinction.

The OSHA construction vocabulary failure mode in detail

The competent-person/qualified-person distinction

The distinction between "competent person" and "qualified person" is the most consequential vocabulary accuracy requirement in OSHA 1926 construction training. OSHA defines both terms at 29 CFR 1926.32:

"Competent person" means one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.

"Qualified person" means one who, by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training, and experience, has successfully demonstrated his ability to solve or resolve problems relating to the subject matter, the work, or the project.

These are distinct OSHA terms with different certification, training, and authority requirements. In many Subpart contexts, the competent person and the qualified person are different individuals with different obligations: in Subpart L (scaffolding), a qualified person must design the scaffold and a competent person must inspect it; in Subpart P (excavation), a competent person must classify soil and must be capable of identifying cave-in hazards, but the design of protective systems more complex than simple sloping must be performed by a registered professional engineer (a specific type of qualified person); in Subpart CC (cranes), the signal person must be "qualified" (as defined in 29 CFR 1926.1419) and the rigger must be "qualified" (29 CFR 1926.1425(c)) or "competent" depending on the specific activity.

A training video that narrates "the competent person must inspect the scaffold before each work shift" — and whose caption track renders this as "the qualified person must inspect the scaffold before each work shift" — has mis-assigned the inspection obligation to the wrong OSHA role category. A hearing-impaired scaffold inspector who was trained that a "qualified person" (implying engineering credentials or formal certification) is required for daily inspection, rather than a "competent person" (a trained employee designated by the employer), may misunderstand who on their crew can legally perform that function. The legal significance is not hypothetical: OSHA cites employers for assigning competent-person functions to unqualified individuals, and the distinction between the two role types is frequently tested in OSHA compliance audits and enforcement actions.

Generic STT has no mechanism to maintain this distinction. Both "competent" and "qualified" are common English adjectives with similar connotations in everyday usage — both mean skilled or capable. STT trained on general text may treat them as synonyms in construction training context, rendering "qualified" where "competent" was narrated or vice versa without the construction safety vocabulary layer that preserves the OSHA definitional distinction.

29 CFR citation format inconsistency

OSHA 1926 construction training video narrates regulatory citations at high frequency. A 30-minute fall protection training module may reference 29 CFR 1926.502 a dozen times (for the fall protection systems standard), 29 CFR 1926.503 several times (for the training requirements), and additional citations from Subpart M for specific system types. Each citation is narrated in a consistent form by the narrator — "twenty-nine C-F-R nineteen-twenty-six dot five-oh-two" — but generic STT produces variant transcriptions of the same citation across different occurrences in the same video:

• "29 CFR 1926.502" (correct — numeral-period-numeral format)
• "29 C.F.R. 1926.502" (CFR with periods — an older formatting convention)
• "29 CFR 1926-502" (hyphen instead of decimal — common STT artefact for decimal-separated regulatory citations)
• "twenty-nine CFR nineteen twenty-six point five oh two" (all words — STT renders the entire citation in word form when the narrator speaks at lower speed or higher emphasis)
• "29 CFR section 1926.502" (with "section" inserted — STT interpolates "section" before the decimal when context triggers the interpolation)
• "29 CFR 1926,502" (comma instead of decimal — a formatting artefact in some STT systems)

Six different transcription variants for a single regulatory citation, across a single training video, create a caption track that is internally inconsistent and unreliable as a reference document. For a hearing-impaired OSHA 10 course participant who is taking notes from the caption track and recording specific OSHA citations to look up later, an inconsistently formatted citation is not reliably findable in the CFR. The GlossCap approach applies consistent citation formatting — "29 CFR 1926.XXX" with the standard decimal-period separator — across all occurrences of any 29 CFR 1926 citation in a construction safety training video.

Subpart letter identification

OSHA 1926 is organised into subparts identified by single capital letters (Subparts A through Z) and two-letter identifiers (Subparts AA, BB, CC, DD, EE, FF, GG). Construction training video references subpart identifiers frequently — "Subpart M for fall protection," "Subpart P for excavation," "Subpart L for scaffolding," "Subpart CC for cranes and derricks," "Subpart AA for confined space." The capital letter identifiers are narrated as letter names ("Subpart M" → "Subpart Em," "Subpart P" → "Subpart Pee," "Subpart L" → "Subpart El," "Subpart CC" → "Subpart See-See," "Subpart AA" → "Subpart Ay-Ay").

STT rendering of these subpart identifiers is inconsistent:

• "Subpart M" → "Subpart M" (correct), "Sub part M" (without hyphen), "subpart M" (lowercase "subpart"), "Subpart m" (lowercase letter)
• "Subpart P" → "Subpart P" (correct), "sub-part pee" (phonetic — the letter P rendered as the word for urination), "Subpart p" (lowercase letter)
• "Subpart L" → "Subpart L" (correct), "sub-part el" (phonetic — "El" is a word for elevated train, not a letter identifier), "Subpart I" (optical confusion in some STT systems between L and I when context is limited)
• "Subpart CC" → "Subpart CC" (correct), "Subpart see-see" (phonetic — looks like a visual indicator, not a regulatory identifier), "Sub part CC" (without hyphen)
• "Subpart AA" → "Subpart AA" (correct), "Subpart A A" (space-separated), "Subpart double A" (phonetic expansion)

SSHO — Site Safety and Health Officer

On federal construction projects — Department of Defense construction, Army Corps of Engineers projects, federal building construction under GSA authority — the contractor is typically required by the contract to designate a Site Safety and Health Officer (SSHO) who is on-site full-time during construction operations. The SSHO requirement appears in EM 385-1-1 (the U.S. Army Corps of Engineers Safety and Health Requirements Manual) and in contract-specific safety plans for federal construction work. Federal construction safety training video — training produced for or distributed to federal construction project workforces — references the SSHO role and its specific qualifications and responsibilities.

"SSHO" narrated as "S-S-H-O" (four letters) or "SSHO" as a word (which produces no stable phonetic rendering — it is not a pronounceable syllable in English). STT variants: "SSHO" (correct), "S S H O" (letter-spaced), "so" (extreme phonetic collapse — four letters reduced to a two-letter word), "S-S-H-O" (hyphenated), "SSH O" (partial collapse). For Section 508-obligated federal construction training content — content produced for or funded by federal agencies for federal construction projects — SSHO must be accurately transcribed as the specific role designation, not collapsed to "so" or rendered as letter-spaced "S S H O" that is unrecognisable to a hearing-impaired viewer reading the caption without the audio context.

MUTCD — Manual on Uniform Traffic Control Devices

Construction projects adjacent to or affecting roadways — highway construction, utility work in road rights-of-way, bridge and infrastructure projects — must implement temporary traffic control (TTC) plans that comply with the Manual on Uniform Traffic Control Devices (MUTCD). MUTCD compliance training for highway and roadway construction workers covers: temporary traffic control zone setup (advance warning area, transition area, buffer space, work area, termination area); traffic control device types (signs, signals, channelising devices); flagger training and hand-signalling procedures; and the specific MUTCD Part 6 standards for temporary traffic control. Flagging certification training — which many states require for all flaggers on highway construction projects — is predominantly video-based and references the MUTCD by name repeatedly.

"MUTCD" narrated as "M-U-T-C-D" (five letters) or "the MUTCD" (as a word — "mut-C-D" or "mutch-dee"). STT variants: "MUTCD" (correct), "M U T C D" (letter-spaced), "mutcd" (lowercase), "M.U.T.C.D." (with periods), "mutch-dee" (phonetic — "mutched" is not a word, but the phonetic rendering produces a plausible-looking nonsense word). In roadway construction safety training, MUTCD Part 6 references must be accurately transcribed for the training to communicate which specific regulatory standard governs the TTC plan requirements being taught.

Compliance obligations for construction safety training video

29 CFR 1926.21 — general construction training obligation

OSHA's general construction training obligation at 29 CFR 1926.21(b)(2) requires that the employer "shall instruct each employee in the recognition and avoidance of unsafe conditions and the regulations applicable to his work environment to control or eliminate any hazards or other exposure to illness or injury." This is the foundational training requirement for all construction employers and all construction workers. It does not specify training format — it does not require video-based training — but it establishes the substantive standard against which all training must be measured: the employee must be instructed in hazard recognition and regulatory compliance. For a hearing-impaired construction worker who cannot access video-based safety training through accurate captions, the 29 CFR 1926.21 substantive training obligation is not met by a video with inaccurate captions. The caption track is the medium through which the instruction is delivered to the hearing-impaired worker; if the caption track does not accurately convey the instruction (substituting "qualified person" for "competent person," mis-transcribing the OSHA citation, rendering "LEL" as "lil"), the instruction is not effectively delivered, and the 29 CFR 1926.21 obligation is not fulfilled.

Subpart-specific training standards

Beyond the general training obligation, individual OSHA 1926 subparts establish specific training requirements with defined content and documentation obligations:

• 29 CFR 1926.503 (fall protection training): requires training for each employee who might be exposed to fall hazards. Training must cover the nature of fall hazards, the correct procedures for erecting, maintaining, disassembling, and inspecting fall protection systems, and the use and operation of guardrail systems, personal fall arrest systems, safety net systems, warning line systems, safety monitoring systems, controlled access zones, and fall protection plans. A training video that inaccurately captions any of these system names or the regulatory citation for each system type fails the 29 CFR 1926.503 training content requirement for hearing-impaired employees.
• 29 CFR 1926.454 (scaffolding training): requires training for each employee who performs work while on a scaffold and for each employee who is involved in erecting, disassembling, moving, operating, repairing, maintaining, or inspecting a scaffold. Training must address the nature of any electrical hazards, fall hazards and falling object hazards, the correct procedures for dealing with such hazards, and the design criteria, maximum intended load-carrying capacity, and intended use of the scaffold.
• 29 CFR 1926.1430 (crane training): requires training for operators, signal persons, riggers, and others working with cranes. Training content requirements are extensive and include equipment capabilities, safe operating procedures, pre-use inspection, and the recognition of potential hazards. Operator certification under 29 CFR 1926.1427 requires third-party accredited testing.
• 29 CFR 1926.1209 (confined space training): requires training for each employee who is to work in permit spaces and for each employee who performs the duties of entry supervisors and attendants. Training must enable each employee to perform their specific duties.

ADA Title I — construction employers

Construction employers with 15 or more employees — which includes all but the smallest construction firms — have ADA Title I employer accommodation obligations for hearing-impaired employees. Construction is a large-employer industry: the major general contractors (Turner Construction, Bechtel, Skanska, Fluor, Kiewit) employ tens of thousands of workers; the major specialty contractors (electrical, mechanical, piping, fire protection) employ workforces of hundreds to thousands; and the typical mid-tier general contractor or specialty contractor employs 50–500 workers. All are subject to ADA Title I.

Hearing-impaired workers are employed in construction — as project managers, safety officers, estimators, schedulers, BIM coordinators, and in field supervision roles. For hearing-impaired construction supervisors whose role requires OSHA 30-hour certification and who receive employer-administered safety training video as part of their ongoing professional development, ADA Title I requires accessible training content. Inaccurate captions on OSHA 10/30 course video modules, on employer safety orientation videos, and on equipment-specific safety training videos do not satisfy the ADA Title I effective-communication standard for these employees.

State plan states — Cal/OSHA, WISHA, MIOSHA

Twenty-six states and territories operate their own occupational safety and health programs — OSHA "state plan states" — that must adopt standards at least as effective as federal OSHA standards. For construction safety training, the most significant state plan states are:

• California (Cal/OSHA): Cal/OSHA Title 8, Section 1510 requires effective safety training in a form that employees can understand, including language accessibility. Cal/OSHA enforces construction safety standards that in some areas are more stringent than federal OSHA 1926 standards (Cal/OSHA's fall protection trigger height is lower for some activities; Cal/OSHA's lead and silica standards in construction are more stringent). California FEHA and the Unruh Act add state-level accessibility obligations on top of ADA Title I for construction employers with California operations.
• Washington (WISHA — Washington Industrial Safety and Health Act): WISHA regulations in WAC 296-155 govern construction safety in Washington State. WISHA adopts federal OSHA 1926 as its baseline with Washington-specific amendments. Washington's large commercial construction sector — Boeing facilities, data centre construction, major public works — generates significant demand for construction safety training video with state-specific regulatory vocabulary (WISHA citations, Washington Department of Labor and Industries enforcement terminology).
• Michigan (MIOSHA — Michigan Occupational Safety and Health Administration): MIOSHA Part 45 governs construction safety in Michigan. Michigan's automotive-adjacent construction sector — plant expansions, manufacturing facility construction, infrastructure projects — requires MIOSHA-specific vocabulary in employer safety training programmes.

State plan state construction training video often references both federal 29 CFR 1926 citations and state-equivalent citations (e.g., "WAC 296-155-24510" for Washington fall protection). The state citation format adds another layer of regulatory citation vocabulary that generic STT handles inconsistently.

Section 503 and VEVRAA — federal contractor construction companies

Construction companies with federal contracts — government building construction, military facility construction, transportation infrastructure funded by federal programs — are federal contractors subject to Section 503 of the Rehabilitation Act and VEVRAA. Section 503 requires federal contractors with contracts above $15,000 to provide equal employment opportunity to qualified individuals with disabilities and to take affirmative action. For construction companies with significant federal contract revenue, the accessible training content obligation is an element of Section 503 compliance in addition to the ADA Title I baseline. Federal construction safety training programmes — those produced for or required by federal contract safety plans — carry the highest vocabulary complexity in the sector because they reference both federal OSHA 1926 standards and the additional safety requirements of federal construction contracts (EM 385-1-1, SSHO requirements, specific federal agency safety programme requirements).

See GlossCap pricing

LMS platforms and delivery context in construction

OSHA Outreach Training Program delivery

OSHA 10 and OSHA 30 construction courses are delivered through OSHA-authorised trainers operating under the OSHA Outreach Training Program. The trainer is individually authorised; OSHA does not authorise training companies or LMS platforms. Online OSHA 10/30 courses — when permitted under the Outreach Training Program, which has historically been restricted for the 30-hour course — are delivered through provider-specific platforms. Authorised online OSHA 10 providers include OSHA Education Center, 360training, and other OSHA-authorised online course providers whose platforms deliver video-based instructional modules with quiz elements. Caption quality on these provider platforms varies: some modules were captioned manually, some with generic STT without regulatory vocabulary tuning, and the regulatory vocabulary failure modes described above are present across the provider landscape.

Alchemy / Intertek Alchemy

Alchemy (now Intertek Alchemy) is a specialist safety training content and LMS platform that serves the food manufacturing, agricultural processing, and construction safety training markets. Alchemy's construction safety content library includes OSHA 10 equivalent modules, hazard recognition training, and equipment-specific safety training. Caption availability on Alchemy construction safety content varies by module; Alchemy's LMS supports caption file upload for customer-produced content.

Procore — construction project management with safety module

Procore is the leading construction project management software platform, used for project scheduling, budgeting, document management, and safety management on construction sites. Procore's Toolbox Talks module and safety observation tools support brief safety communications on active projects. Some construction companies distribute safety training video through Procore's document and observation management workflows rather than through a dedicated LMS. Caption support in Procore for video content is limited and does not include auto-generation of construction safety vocabulary.

NCCER — National Center for Construction Education and Research

NCCER (National Center for Construction Education and Research) develops craft training curricula and assessment programmes used by construction trade education organisations, apprenticeship programmes, and construction employers for craft skills training. NCCER curricula cover all construction crafts — carpentry, electrical, HVAC, plumbing, masonry, rigging, scaffolding, concrete — and include safety training components integrated into each craft curriculum. NCCER training content is distributed through NCCER-accredited training sponsors (community colleges, trade schools, union training programs, employer training programs). Caption quality on NCCER video content varies by the specific curriculum module and the age of the content; NCCER has invested in captioning accessibility for newer curriculum editions.

ComplianceQuest and EHS management platforms

ComplianceQuest is an EHS (Environment, Health, and Safety) management platform that includes safety training management, incident investigation, and corrective action workflows for industrial and construction employers. ComplianceQuest's training module supports video-based safety training assignment, completion tracking, and compliance reporting. Caption file upload is supported; no auto-generation of construction safety vocabulary. Larger construction companies using ComplianceQuest as their primary EHS management system use it as the LMS for employer-administered safety training programmes.

iSN/Avetta/Veriforce — contractor management platforms

Contractor management platforms — ISN (now ISNetworld), Avetta, and Veriforce — are used by large owner-operators (oil and gas companies, utilities, petrochemical plants, major industrial facilities) to qualify and monitor the safety performance of contractor companies working on their sites. These platforms typically require contractors to upload documentation of safety training completion — including OSHA certifications, equipment-specific training records, and site-specific safety induction records. Some contractor management platforms are expanding into training delivery, hosting safety training video modules that contractors must complete as a condition of approved vendor status. Caption quality on contractor management platform-hosted training video is inconsistent and construction safety vocabulary captioning is not specifically addressed by any of the major platforms.

Caterpillar Safety Training and OEM safety content

Heavy equipment manufacturers — Caterpillar, Komatsu, Manitowoc Cranes, Tadano, Liebherr — produce operator safety training video for their specific equipment models. Caterpillar's Safety Training content library covers equipment-specific pre-operational inspection, safe operating procedures, and load-handling safety for Cat-branded machines. This content narrates equipment model names (Cat 336 excavator, Cat 745 articulated truck, Cat D8 dozer — using the specific model designation that Caterpillar uses, not the generic equipment type name), machine-specific control names (Joystick Steering and Propulsion — JSP — for Cat articulated trucks; STICS — Steering and Transmission Integrated Control System — for Cat dozers), and equipment-specific safety systems (KOMTRAX fleet management for Komatsu equipment, Crane Control System — CCS — for Manitowoc cranes). All of these model designations and system names are out-of-distribution for generic STT and require OEM equipment vocabulary in the company-specific glossary overlay.

The GlossCap approach for construction safety training

Construction safety training vocabulary has a large shared base layer — the full 29 CFR 1926 regulatory vocabulary that is consistent across all construction employers — combined with a site- and employer-specific overlay that covers particular equipment models, site area designations, subcontractor names, and employer-specific safety management system vocabulary.

The shared base layer covers: all 29 CFR 1926 subpart references (Subparts A through Z, AA through GG) with consistent subpart-letter capitalisation; all Focus Four hazard vocabulary (fall protection, struck-by, electrical, caught-in/between) and the specific regulatory citations for each (1926.502 fall protection, 1926.401–449 electrical, 1926.201–203 signalling, 1926.600–606 equipment); the OSHA-defined personnel role terms (competent person, qualified person, designated person, signal person, qualified rigger, competent rigger, lift director, entry supervisor, authorised entrant, attendant) with consistent capitalisation as OSHA terms of art; fall protection PPE vocabulary (PFAS, SRL, anchorage, D-ring, lanyard, deceleration device, snap hook, carabiner, lifeline, guardrail, safety net); crane and rigging vocabulary (load chart, rigging, sling, hitch, shackle, at-two-block A2B, boom, jib, luffing jib, lattice boom, telescoping boom, swing radius, travel path); scaffold vocabulary (tube-and-coupler, mast-climbing, systems scaffolding, suspended scaffold, boatswain's chair); excavation vocabulary (Type A/B/C soil, sloping, benching, shoring, trench box); electrical safety vocabulary (NFPA 70E, arc flash, arc-rated, ATPV, cal/cm², PPE Category 1/2/3/4, lockout/tagout, LOTO); confined space vocabulary (IDLH, LEL, O2 deficiency and enrichment, authorised entrant, attendant, entry supervisor, permit-required confined space); and state plan state citation vocabulary (WAC 296-155, MIOSHA Part 45, Cal/OSHA Title 8 Section 1510, SSHO for federal construction projects, MUTCD Part 6 for highway construction).

The company-specific overlay covers: specific equipment model names and system designations used at the employer (specific crane models with rated capacities, specific excavator models, specific scaffold system brands — Layher, Safway, Bil-Jax — and their model names); site-specific area designations for active construction projects; subcontractor company names referenced in site safety induction content; employer-specific safety management system names and safety report form identifiers; and any employer-specific safety programme terminology (proprietary safety observation programme names, internal safety metric names, internal safety performance indicator names) that appears in company-produced safety training video content.

FAQ — construction safety training captions

Further reading

• Safety training video captions: OSHA, MSHA, and HazCom vocabulary
• Compliance training video captions: SOX, HIPAA, GDPR acronym vocabulary
• ADA Title I captions: employer accommodation for construction safety training
• WCAG 2.1 AA captions: what SC 1.2.2 "accurately convey the audio" requires
• Section 508 captions: federal contractor obligations for construction companies
• Manufacturing training captions: industrial safety and operations vocabulary
• HazCom training captions: chemical names, IUPAC vocabulary, and OSHA 1910.1200
• Why 99% caption accuracy matters: the WCAG 2.1 AA threshold for safety training
• Glossary-biased captioning: engineering and technical vocabulary in Whisper STT