Supervisor duties under OSHA and state plans

On a construction site, the person who most shapes whether workers go home unhurt is not the safety coordinator, the owner or the inspector. It is the supervisor who assigns the work, decides how it will be done and is standing nearby when it happens. This course is about that role. CON-305 introduced the superintendent's job and gave a first overview of supervisors' legal duties, due diligence and personal liability. This course goes further: it treats safety as a core part of supervising construction work and follows the Larkspur Commons team through a year of planning, hazard assessment, inspections, incidents, high-risk work and culture building.

Larkspur Commons is the six-story building of 112 rental homes over shops in Boise, Idaho, that has run through the whole track: a two-story concrete podium and four stories of wood frame, built by Thornbury Builders for about $48 million over 20 months. Dana Whitfield is the superintendent, Omar Haddad the assistant superintendent and Mei Lin the field engineer. For this course Thornbury has added a site safety coordinator, Priya Sandhu, who works across two Thornbury sites. Priya advises, audits and trains; she does not supervise the crews. That distinction is the first lesson of the course: safety is a line responsibility, and the safety coordinator supports the line rather than replacing it.

Who is a supervisor?

US federal law does not give supervisors a separate set of duties in the way Canadian provincial laws do. The Occupational Safety and Health Act places its duties on employers, and the employer acts through its supervisors. In practice, when an OSHA compliance officer asks who was in charge of the work, the answer is the supervisor, and what the supervisor knew or should have known is treated as what the employer knew. A foreman's knowledge of an unguarded floor edge is the employer's knowledge. The title does not matter: a lead hand who directs a small crew is acting for the employer when he does. On Larkspur Commons that means Dana and Omar, every Thornbury foreman and lead hand, and every subcontractor foreman, carry the employer's duties for the work they direct.

A worker who directs others for a single task is a supervisor for that task. When Omar sends an apprentice carpenter with a journeyman to install guardrails on level 4, the journeyman directs the apprentice's work and is responsible for doing it safely. Thornbury's site rules make this explicit: anyone who directs the work of another worker is expected to know the hazards of that work and to make sure the controls are in place before it starts.

What the law requires of supervisors

The OSH Act's general duty clause requires each employer to furnish a workplace free from recognized hazards that are causing or likely to cause death or serious physical harm, and to comply with the standards. For construction, the standards are in 29 CFR Part 1926. Subpart C sets general requirements: employers must initiate and maintain programs for frequent and regular inspections by competent persons, must instruct each employee in recognizing and avoiding unsafe conditions and the regulations that apply, and must not require any employee to work in conditions that are unsanitary, hazardous or dangerous to health or safety. Specific subparts then add duties for particular work. Many of those duties are written around a competent person, which in practice is usually the supervisor.

Prime contractors, controlling employers and multi-employer sites

A construction site has many employers. OSHA handles that with its multi-employer citation policy, introduced in CON-305. On a multi-employer worksite, more than one employer may be cited for the same hazardous condition: the creating employer that caused it, the exposing employer whose workers were exposed, the correcting employer responsible for fixing it, and the controlling employer with general supervisory authority over the site. As general contractor under the AIA A201 contract, Thornbury is the controlling employer on Larkspur Commons. A controlling employer must exercise reasonable care to prevent and detect violations, which in practice means inspecting the site at reasonable intervals, requiring subcontractors to correct hazards and following up. That does not relieve each subcontractor of its own duties. Ridgeline Framing still has to train, supervise and equip its own crews; Thornbury has to make sure the pieces fit together.

The practical result is the same in both countries. The general contractor's superintendent cannot say that a subcontractor's unsafe practice is the subcontractor's problem. Dana is expected to notice it, to require it to be corrected, and to follow up if it is not. Lesson 4 covers how Thornbury prequalifies subcontractors and holds them to the site rules.

The competent person and the qualified person

The 1926 standards repeatedly require a competent person, defined in 1926.32(f) as one who is capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary, hazardous or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them. Subpart P requires a competent person to inspect excavations daily and after rain; Subpart L requires one to inspect scaffolds before each shift; Subpart M requires one to supervise safety monitoring systems and fall protection training; Subpart CC requires one for many crane and rigging tasks. Authority is part of the definition. A worker who can spot a hazard but cannot stop the work is not a competent person under OSHA's definition.

Each week Omar checks the look-ahead schedule (CON-335) against a simple list: which activities next week need a qualified or competent person, and who it will be. If an activity has no name against it, the activity is not ready.

# Next week's high-risk activities and their designated checker (illustrative)
activities = [
    ("storm line trench, gridline A", "excavation", "Omar Haddad"),
    ("east elevation scaffold raise", "scaffold", "R. Gill (scaffold contractor)"),
    ("level 5 leading-edge framing", "fall protection", "B. Kowalski"),
    ("wall panel picks, levels 5-6", "rigging", "T. Moreau (rigger)"),
    ("roof membrane torch-on, podium", "hot work", None),
    ("temporary power to level 6", "electrical", "Ashgrove Electric lead hand"),
]
ready = [a for a in activities if a[2]]
missing = [a for a in activities if not a[2]]
print(f"{len(ready)} of {len(activities)} activities have a designated checker")
for name, kind, _ in missing:
    print(f"NOT READY: {name} ({kind}) has no qualified or competent person assigned")

5 of 6 activities have a designated checker
NOT READY: roof membrane torch-on, podium (hot work) has no qualified or competent person assigned

The torch-on roofing at the podium had no name because the roofing subcontractor had changed its foreman. Omar phoned the subcontractor that afternoon, and the new foreman's hot work training record was in the site file before the work started.

Workers' rights that supervisors must respect

US workers have a narrower right to refuse than Canadian workers. Under OSHA's regulations, a worker may refuse a task when they believe in good faith that it poses an imminent danger of death or serious injury, a reasonable person would agree, there is not enough time to get the hazard corrected through regular channels, and the employer has refused to fix it. Section 11(c) of the OSH Act protects workers from retaliation for reporting injuries or hazards, filing complaints and exercising other rights. A supervisor who responds to a safety complaint with anger or a threat, or who quietly gives the worker fewer hours, exposes the employer to an 11(c) claim and teaches the whole crew to stay silent. Thornbury's site rules give every worker on Larkspur Commons a broader stop-work authority than the law requires, covered in lesson 6.

Dana's approach to a refusal is simple: thank the worker, stop the task, look at the hazard together, and fix it or explain it. Most refusals on a construction site are not legal disputes. They are a worker telling the supervisor something the supervisor needs to know.

Regulators and where Larkspur Commons sits

Idaho has no OSHA-approved state plan for private employers, so federal OSHA enforces the OSH Act on Larkspur Commons through its Boise area office. About half the states run their own state plans, which must be at least as effective as federal OSHA and often go further. Thornbury also builds in Washington, where the Department of Labor and Industries (DOSH) enforces its own construction rules, including required crew safety meetings and accident prevention programs, and in Oregon, where Oregon OSHA has its own rules for construction. Supervisors who move between states need to check whether a state plan applies; the principles carry over but the details do not.

This course gives the rules for the Larkspur Commons jurisdiction in detail and mentions others for comparison. HSE-375, Constructor and Supervisor Responsibilities on Construction Projects, in the Safety Training stream, covers the legal framework in more depth for those who need it.

Safety as part of supervising, not an add-on

A supervisor who treats safety as a separate job, something the safety coordinator does on Thursdays, will find that the work is planned without it and the hazards are discovered when someone is hurt. Dana's view, which this course follows, is that a job is not well planned unless it is planned to be done safely, and a crew is not well led unless it is led to work safely. The same habits that produce good schedules and good quality, covered in CON-335 and CON-345, produce safe work: thinking ahead, checking before work starts, setting clear expectations, following up and learning from what goes wrong.

Lesson 2 turns to due diligence: how a supervisor shows, with records and actions, that they took every reasonable precaution. Lessons 3 to 8 cover the systems a supervisor runs every day: site safety plans, orientations, hazard assessments, toolbox talks, inspections and incident investigations. Lessons 9 and 10 cover the high-risk work that causes most serious injuries in construction, and lesson 11 covers safety culture. Lesson 12 puts it all together in a safety leadership plan for a new project.