Construction · Lesson 9 of 13Beginner8 min read

Jobsite Safety

OSHA, the federal workplace safety agency, calls construction a high-hazard industry. Most of the danger comes from a handful of well-understood hazards. Here’s what OSHA’s rules and guidance say about each one.

The Focus Four

OSHA puts it plainly: “The top four causes of construction fatalities are: Falls, Struck-By, Caught-In/Between and Electrocutions.” OSHA’s training calls them the Construction Focus Four, and every 10- and 30-hour construction Outreach course has to cover them. Falls lead the list. In 2024, 389 of the 1,034 construction workers who died on the job were killed in falls to a lower level.

OSHA: “The top four causes of construction fatalities are: Falls, Struck-By, Caught-In/Between and Electrocutions.” Source: OSHA QuickCard 3216.

Falls and the 6-foot rule

In residential construction, OSHA’s standard says each worker 6 feet or more above a lower level must be protected by a guardrail system, a safety net system or a personal fall arrest system. OSHA also allows an effective fall restraint system in place of fall arrest. Some details from OSHA’s guidance for roofing work:

A personal fall arrest system is an anchor, a full-body harness, and a lifeline or lanyard. The anchor should go into a structural member, not just the sheathing. Body belts aren’t allowed for fall arrest.
The top rails of a guardrail system must be 39 to 45 inches above the walking surface.
Covers over holes and skylights must hold at least twice the load expected on them, be secured, and be marked “HOLE” or “COVER.”

OSHA’s campaign boils fall prevention down to three words: Plan ahead, Provide the right equipment, and Train everyone to use it.

Ladders

OSHA’s ladder rules for construction include these:

Set an extension ladder so its base is about one-quarter of its working length out from the wall (4 up for every 1 out).
When a ladder is used to get onto a roof or other landing, its side rails must extend at least 3 feet above the landing.
Face the ladder when climbing up or down, keep three points of contact (two hands and a foot, or two feet and a hand), and don’t carry tools in your hands while climbing.
Never use the top or top step of a stepladder as a step.
Use ladders only for what they were designed for, and don’t lay an extension ladder flat as a platform.
Keep ladders and other tools at least 10 feet from power lines, and use ladders with nonconductive side rails where they could touch energized electrical equipment.
Inspect ladders before use. Mark a damaged ladder “Do Not Use” and take it out of service until it’s repaired.

From OSHA’s rules and guidance for construction: base out about ¼ of the working length, side rails at least 3 ft above the landing, face the ladder, keep 3 points of contact, and keep ladders and tools at least 10 ft from power lines. Sources: OSHA 29 CFR 1926.1053; OSHA Fact Sheet 3660.

Struck-by and caught-in

To prevent struck-by injuries, OSHA says never to position yourself between moving and fixed objects, and to wear high-visibility clothing near equipment and vehicles.

Trenches are the classic caught-in hazard. OSHA’s rules:

Trenches 5 feet deep or more need a protective system (sloping, shoring, benching or a trench shield), unless they’re dug entirely in stable rock. Some shallower trenches need one too.
Trenches 20 feet deep or more need a protective system designed by a registered professional engineer, or based on tabulated data a professional engineer prepared or approved.
Keep excavated soil and other materials at least 2 feet back from the edge.
A competent person must inspect trenches daily and as conditions change, before anyone goes in. Trenches more than 4 feet deep get tested for low oxygen and toxic gases.

Electrocution

OSHA’s precautions: locate and identify utilities before starting work; look for overhead power lines when operating any equipment and keep a safe distance from them; use portable electric tools only if they are grounded or double-insulated; use ground-fault circuit interrupters (GFCIs); and be alert to electrical hazards when working on ladders, scaffolds or other platforms. The Electrical course explains how GFCIs work.

Power tools and nail guns

OSHA’s five basic rules for hand and power tools: keep tools in good condition with regular maintenance; use the right tool for the job; examine each tool for damage before use, and don’t use damaged tools; operate tools according to the manufacturer’s instructions; and use the right personal protective equipment. Also:

Never carry a tool by its cord or hose.
Disconnect tools when they’re not in use, before servicing or cleaning them, and when changing blades, bits or other accessories.
Never remove safety guards while the tool is in use. A portable circular saw needs an upper guard over the whole blade and a lower guard that retracts as it cuts and springs back when the saw is lifted out.
Clamp or vise the work so both hands are free for the tool, and keep good footing and balance.

Nail guns cause an estimated 37,000 emergency-room visits a year, and they put more construction workers in the hospital than any other tool. OSHA says the risk of injury is twice as high with a multi-shot contact trigger as with a single-shot sequential trigger.

Personal protective equipment

Personal protective equipment, or PPE, is gear worn to reduce exposure to hazards: gloves, safety glasses and shoes, earplugs or muffs, hard hats, respirators, coveralls and vests. OSHA treats it as the protection to use when engineering, work-practice and administrative controls aren’t feasible or aren’t enough on their own. Employers must provide PPE and train workers in when it’s needed and how to wear it. The Bureau of Labor Statistics says carpenters typically wear boots, hard hats, eye protection and reflective vests.

Silica, lead and asbestos

Silica. Quartz is a basic component of sand and granite, and cutting, drilling or grinding concrete, brick, block or stone throws up fine crystalline silica dust. OSHA says breathing it causes silicosis, an incurable lung disease that leads to disability and death, as well as lung cancer, chronic obstructive pulmonary disease (COPD) and kidney disease. Controls include saws that feed water continuously to the blade, ventilation, a HEPA-filtered wet vacuum for the slurry, and respirators.

Lead. Homes built before 1978 may have lead-based paint. Anyone paid to disturb paint in those homes must be EPA-certified and work lead-safe (Lesson 7).

Asbestos. EPA says you generally can’t tell whether a material contains asbestos just by looking at it. Leave material in good condition alone, have it inspected before a remodel that could disturb it, and never dust, sweep or vacuum debris that may contain it.

The Focus Four and OSHA’s key precautions
Hazard	OSHA precautions
Falls	Fall arrest equipment, perimeter protection, secured and labeled covers over floor openings, ladders and scaffolds used safely.
Struck-by	Never stand between moving and fixed objects; wear high-visibility clothes near equipment and vehicles.
Caught-in or between	Never enter an unprotected trench 5 feet or deeper; protect trenches by sloping, shoring, benching or trench shields.
Electrocution	Locate utilities, watch for overhead power lines, use grounded or double-insulated tools and GFCIs.

StopKnow when the job needs more than you have

Work at height, trenches, structural demolition and anything involving lead paint or possible asbestos need training, equipment and often certification. If the job needs fall protection you don’t have or know how to use, a trench box, or a respirator fitted to you, it belongs with a trained crew.

Check yourself

Tap an answer to check it, or open “Show the answer.”

Which four hazards does OSHA call the top causes of construction deaths?
Show the answer
Falls, struck-by, caught-in or between, and electrocution. OSHA’s Focus Four. Falls are the leading cause.
In residential construction, OSHA requires fall protection for workers how high above a lower level?
Show the answer
6 feet or more. 6 feet or more: guardrails, safety nets or personal fall arrest systems.
When you climb an extension ladder onto a roof, its side rails must extend how far above the roof edge?
Show the answer
3 feet. At least 3 feet above the upper landing.
At what depth does OSHA require a protective system for a trench, unless it’s in stable rock?
Show the answer
5 feet. 5 feet or more, and some shallower trenches need one too. At 20 feet, an engineer designs it.
Which nail gun trigger carries about half the injury risk of a multi-shot contact trigger?
Show the answer
A single-shot sequential trigger. OSHA says the risk is twice as high with a multi-shot contact trigger.

Go deeper

OSHA QuickCard: Top Four Construction Hazards (OSHA 3216) OSHA’s QuickCard on the top four construction hazards.
OSHA: Protecting Roofing Workers (OSHA 3755) OSHA’s guide to protecting roofing workers.
OSHA Fact Sheet: Reducing Falls in Construction: Safe Use of Extension Ladders (OSHA 3660) OSHA’s fact sheet on extension ladders.
OSHA: Hand and Power Tools (OSHA 3080) OSHA’s booklet on hand and power tools.
OSHA: Crystalline Silica, Health Effects What silica dust does to the lungs and kidneys.
OSHA Outreach Training Program: Program Overview OSHA’s 10- and 30-hour Outreach Training courses.

Sources

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A free course from Teddy Rook Book. It explains how houses are built in general and follows U.S. sources; the local building code, the building department and the manufacturer’s instructions are the final word.