OSHA 30 Construction — All Questions
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94 questions
For a simple sloped excavation in Type C soil, what is the maximum allowable slope?
- a.Vertical walls at 90 degrees
- b.One-quarter horizontal to 1 vertical under most routine jobsite conditions
- c.1.5 horizontal to 1 vertical (about 34 degrees)✓
- d.Straight walls with no slope at all
Under 29 CFR 1926 Subpart P Appendix B, Type C soil must be sloped no steeper than 1.5 to 1, roughly a 34-degree angle from horizontal. Less stable soil needs flatter slopes. Sloping is one protective-system option.29 CFR 1926 Subpart P App B
Before digging begins, underground utility installations should be:
- a.Located and marked, then supported or protected during the work✓
- b.Assumed simply not to exist there as some contractors interpret the rule
- c.Left entirely to random chance
- d.Cut through without any checking
Under 29 CFR 1926.651(b), the estimated location of utility installations must be determined before excavation, often by calling the one-call (811) service. Utilities are supported or protected during work. Striking a gas or electric line can be deadly.29 CFR 1926.651(b)
A trench box (shield) used in an excavation must:
- a.Be made from ordinary cardboard
- b.Cover only half of the workers
- c.Be rated for the depth and soil and protect workers inside✓
- d.Sit 5 feet above the trench bottom when the crew is short on time
Under 29 CFR 1926.652, trench shields must be designed for the loads of the excavation and installed so workers are protected, with workers staying within the protected zone. Manufacturer tabulated data governs its use. Shields are one accepted protective system.29 CFR 1926.652
When water accumulates in an excavation, workers may only continue if:
- a.The trench simply appears to be fine according to older industry practice
- b.They work faster to finish sooner
- c.They ignore the standing water
- d.Special support, water removal, or harnesses and controls are used✓
Under 29 CFR 1926.651(h), workers must not work in excavations with accumulated water unless precautions such as special support, water removal, or harnesses and lifelines are taken. Water undermines trench walls and raises collapse risk. A competent person monitors the conditions.29 CFR 1926.651(h)
Protective systems for excavations deeper than 20 feet must be designed by:
- a.A registered professional engineer✓
- b.Any general worker on the site
- c.The nearest available truck driver
- d.The equipment rental counter clerk
Under 29 CFR 1926.652, protective systems for excavations over 20 feet deep must be designed by a registered professional engineer. Shallower systems may use tabulated data or the appendices. Deep excavations carry the highest cave-in risk.29 CFR 1926.652
When mobile equipment operates near an excavation and the operator cannot see the edge, what is required?
- a.Barricades, hand or mechanical signals, or stop logs✓
- b.Nothing at all is required
- c.A note left back in the office
- d.A single cone placed a mile away for the majority of standard tasks
Under 29 CFR 1926.651(f), when equipment operates near the edge and the operator cannot see it, a warning system such as barricades, hand or mechanical signals, or stop logs must be used. This prevents equipment from rolling into the trench. It also protects workers inside.29 CFR 1926.651(f)
A scaffold and its components must support their own weight plus at least how many times the maximum intended load?
- a.Exactly 1 time the load
- b.Only one-half of the load based on the project's own schedule
- c.4 times the maximum intended load✓
- d.A full 10 times the load
Under 29 CFR 1926.451(a), scaffolds must support their own weight and at least 4 times the maximum intended load. Suspension ropes and hardware use a 6-to-1 safety factor. These margins prevent overloading failures.29 CFR 1926.451(a)
Beyond a 4-to-1 height-to-base ratio, a supported scaffold must be:
- a.Weighted only with loose bricks
- b.Painted for added stability
- c.Restrained from tipping by guying, tying, or bracing✓
- d.Left free-standing at any height in the absence of a written program
Under 29 CFR 1926.451(c), supported scaffolds more than 4 times as tall as their minimum base width must be restrained from tipping by guys, ties, or braces at required intervals. This prevents overturning. Tall scaffolds are especially vulnerable to wind and load shifts.29 CFR 1926.451(c)
How must workers gain access to a scaffold platform?
- a.By jumping from an adjacent roof
- b.By a ladder, stair tower, ramp, or other designed access✓
- c.By being lifted by hand in a bucket
- d.By climbing the diagonal cross braces as a general rule of thumb on site
Under 29 CFR 1926.451(e), safe access such as a ladder, stairway, or ramp must be provided when the platform is more than 2 feet above or below a point of access. Cross braces are not acceptable access. Climbing braces causes falls.29 CFR 1926.451(e)
Suspension scaffold ropes must have a safety factor of at least:
- a.2 to 1
- b.1 to 1
- c.6 to 1✓
- d.1 to 2
Under 29 CFR 1926.451(a), suspension ropes and connecting hardware must support at least 6 times the maximum intended load. This higher factor reflects the consequences of a suspension failure. Ropes are inspected before each use.29 CFR 1926.451(a)
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Who must supervise the erection, moving, and dismantling of scaffolds?
- a.No particular person at all
- b.A competent person✓
- c.A visiting client or guest
- d.The newest apprentice on site
Under 29 CFR 1926.451(f), scaffold erection, moving, dismantling, and alteration must be done under the supervision of a competent person and by trained, experienced workers. This reduces collapse and fall risk during the most dangerous phases. A qualified person designs the scaffold.29 CFR 1926.451(f)
Who must train each employee who works on a scaffold to recognize its hazards?
- a.Any coworker with a smartphone
- b.No one; training is not needed
- c.The manufacturer's website alone
- d.A qualified person✓
Under 29 CFR 1926.454, a qualified person must train each employee who works on a scaffold to recognize the hazards and understand the procedures to control them. Retraining is required when conditions or the scaffold type change. Training reduces scaffold falls and collapses.29 CFR 1926.454
When a break in elevation of 19 inches or more exists and no ramp or runway is provided, OSHA requires:
- a.Only a posted warning sign
- b.A stairway or a ladder✓
- c.Nothing at all is required
- d.A rope to slide down on
Under 29 CFR 1926.1051, a stairway or ladder must be provided at all points of access where there is a break in elevation of 19 inches or more and no ramp, runway, or hoist is in place. This prevents falls and awkward climbs. It is a core Subpart X requirement.29 CFR 1926.1051
A stairway with four or more risers, or rising more than 30 inches, must have:
- a.A loose rope draped across it
- b.No railing of any kind at all
- c.At least one handrail and stair rail✓
- d.A ladder bolted across the steps provided the weather stays clear
Under 29 CFR 1926.1052, stairways with 4 or more risers or rising more than 30 inches must have at least one handrail and a stair rail along each unprotected side or edge. Handrails help prevent falls on stairs. Temporary stairs need the same protection.29 CFR 1926.1052
Portable ladder rungs must be spaced how far apart and be uniform?
- a.Spacing does not matter at all
- b.Between 24 and 30 inches apart
- c.Between 2 and 4 inches apart
- d.Between 10 and 14 inches apart✓
Under 29 CFR 1926.1053, ladder rungs must be spaced between 10 and 14 inches apart and be parallel, level, and uniform. Uniform spacing prevents missteps. Rungs must also be slip-resistant.29 CFR 1926.1053
How must a worker face while climbing a ladder?
- a.Toward the ladder, using three points of contact✓
- b.Away from the ladder to watch below as long as the tools look intact
- c.Backward to keep an eye on traffic
- d.Sideways while carrying heavy tools
Under 29 CFR 1926.1053(b), workers must face the ladder when climbing and maintain three points of contact. Tools should be hoisted or carried in a belt, not in the hands. This reduces the risk of falls.29 CFR 1926.1053(b)
Portable ladders must generally be capable of supporting at least how many times the maximum intended load?
- a.Exactly the load with no margin for most residential-scale jobs
- b.A full 20 times the load
- c.One-quarter of the load
- d.4 times the maximum intended load✓
Under 29 CFR 1926.1053, ladders must support at least 4 times the maximum intended load, with extra-heavy-duty type 1A ladders held to higher requirements. Overloading a ladder can cause sudden failure. Users must observe the duty rating.29 CFR 1926.1053
Why should ladders with conductive (metal) side rails be avoided near electrical work?
- a.Metal can conduct electricity and cause electrocution✓
- b.Metal ladders are simply too heavy
- c.Metal ladders rust almost instantly
- d.Metal ladders are illegal everywhere when only one worker is involved
Under 29 CFR 1926.1053(b), portable ladders with conductive siderails may not be used near energized electrical equipment where the worker or ladder could contact the electricity. Non-conductive fiberglass ladders are used for electrical work. Metal ladders create an electrocution path.29 CFR 1926.1053(b)
Electrocution is one of the Focus Four. Which situation is a leading construction electrocution hazard?
- a.Standing near an ordinary light switch under most routine jobsite conditions
- b.Using a battery-powered flashlight
- c.Reading a monthly electricity bill
- d.Contact with overhead or buried power lines✓
Contact with overhead and buried power lines is a leading electrocution hazard in construction, especially with cranes, ladders, and scaffolds. Under 29 CFR 1926.416, workers must maintain safe clearances and assume lines are live. Electrocution is one of the deadly Focus Four.29 CFR 1926.416
Which practice reduces struck-by injuries in a highway work zone?
- a.Letting workers stand in live traffic lanes as some contractors interpret the rule
- b.Removing all signs to speed up traffic
- c.A temporary traffic control plan with signs, devices, and flaggers✓
- d.Turning off all of the warning lights
Under 29 CFR 1926 Subpart G and the MUTCD, work zones require a traffic control plan with advance warning signs, channelizing devices, and trained flaggers. High-visibility apparel is also required. These controls separate workers from moving traffic.29 CFR 1926.201
High-visibility warning garments for flaggers protect against which hazard?
- a.Loud noise
- b.Chemical burns
- c.Falls from height when the crew is short on time
- d.Being struck by moving vehicles✓
Under 29 CFR 1926.201, flaggers must wear high-visibility garments so drivers can see them, reducing struck-by risk from vehicles. Warning garments are required day and night, with retroreflective material at night. Visibility is the flagger's main protection.29 CFR 1926.201
Reinforcing steel (rebar) onto which workers could fall must be:
- a.Guarded with covers to prevent impalement✓
- b.Sharpened to make work easier
- c.Left exposed and sharp for the crew according to older industry practice
- d.Painted but still left uncapped
Under 29 CFR 1926.701(b), all protruding reinforcing steel onto or into which workers could fall must be guarded to eliminate the hazard of impalement. Rebar caps or troughs are commonly used. Impalement is a severe struck-by and fall consequence.29 CFR 1926.701(b)
What is the main purpose of a barricade around a hazardous area?
- a.To store extra hand tools
- b.To provide seating for breaks
- c.To keep unauthorized workers out of the danger zone✓
- d.To decorate the construction site unless a supervisor decides otherwise
Barricades physically separate workers from hazards such as swing radii, drop zones, and open excavations. Under 29 CFR 1926.202, they are used with signs and tags. Keeping people out of the danger zone prevents struck-by and caught-in injuries.29 CFR 1926.202
Danger signs on a construction site indicate:
- a.A good place to take a lunch break for the majority of standard tasks
- b.The company's daily business hours
- c.Immediate hazards where special precautions are necessary✓
- d.The directions to the parking lot
Under 29 CFR 1926.200, danger signs are used only where an immediate hazard exists and special precautions are needed; they use red, black, and white. Caution signs warn of potential hazards. Standardized signage speeds hazard recognition.29 CFR 1926.200
A 'Do Not Use' or 'Out of Service' tag on equipment serves what purpose?
- a.To show the battery is fully charged based on the project's own schedule
- b.To warn workers not to operate the unsafe equipment✓
- c.To show the equipment is brand new
- d.To advertise the equipment for sale
Accident-prevention tags under 29 CFR 1926.200(h) warn of hazards such as defective tools or equipment out of service. They stay in place until the hazard is eliminated. Tags supplement, but do not replace, guarding or lockout.29 CFR 1926.200(h)
Fire extinguishers rated for which class are used on ordinary combustibles like wood and paper?
- a.Class A✓
- b.Class B for flammable liquids
- c.Class D for combustible metals
- d.Class C for energized electrical
Class A extinguishers are for ordinary combustibles such as wood, paper, and cloth. Class B is for flammable liquids, Class C for energized electrical, and Class D for combustible metals. Under 29 CFR 1926.150, appropriate firefighting equipment must be provided.29 CFR 1926.150
On a construction site, how far, at most, should a worker travel to reach a fire extinguisher for ordinary combustibles?
- a.Up to a half mile away
- b.The distance does not matter
- c.No more than 100 feet✓
- d.No more than 5 feet
Under 29 CFR 1926.150, a fire extinguisher rated at least 2A must be provided so the travel distance to the nearest unit does not exceed 100 feet. Extinguishers must be accessible and maintained. Quick access limits fire spread.29 CFR 1926.150
Flammable liquids in a construction area must be stored in:
- a.Approved closed containers and safety cans✓
- b.Ordinary paper grocery bags
- c.Open buckets set near heaters
- d.Uncovered glass jars in sunlight where the foreman signs off on it
Under 29 CFR 1926.152, flammable liquids must be kept in approved closed containers or safety cans and stored away from ignition sources. Quantities in work areas are limited. Proper storage prevents fires and vapor buildup.29 CFR 1926.152
Compressed gas cylinders in storage must be:
- a.Stacked freely without any restraint
- b.Laid loose on their sides near sparks once the initial setup is complete
- c.Secured upright with valve caps on and away from heat✓
- d.Stored right next to open flames
Under 29 CFR 1926.350, compressed gas cylinders must be secured to prevent tipping, kept with valve protection caps in place when not in use, and separated from ignition sources. Oxygen and fuel-gas cylinders are stored apart. A falling cylinder can rupture violently.29 CFR 1926.350
How often must a portable fire extinguisher be checked?
- a.Only after it is completely used up
- b.Only when the whole site closes down for typical light-duty operations
- c.Periodically, with an annual maintenance check✓
- d.Never once it has been installed
Under 29 CFR 1926.150, portable extinguishers must be inspected periodically and maintained, including an annual maintenance check. Monthly visual checks confirm they are charged and accessible. Neglected extinguishers may fail in an emergency.29 CFR 1926.150
Which is a recognized control for the caught-in hazard of a rotating auger or drilling equipment?
- a.Reaching into it while it rotates
- b.Removing all guards for more speed
- c.Guarding and keeping clothing, hair, and hands clear✓
- d.Wearing loose sleeves near the auger when working away from the edge
Rotating augers and drills can catch clothing and limbs, a caught-in/between hazard. Under 29 CFR 1926.300, moving parts must be guarded and workers keep clear. Loose clothing and jewelry must be avoided near rotating equipment.29 CFR 1926.300
A powered concrete saw or grinder should have which feature to reduce struck-by from the blade?
- a.A cracked blade for flexibility
- b.No guard, for better visibility provided the weather stays clear
- c.A guard removed to save weight
- d.A blade guard positioned to protect the operator✓
Under 29 CFR 1926.300 and 1926.303, abrasive wheels and saws must have guards that cover the spindle end and protect the operator from the wheel. Cracked or damaged wheels must not be used. Guards contain fragments if a wheel shatters.29 CFR 1926.303
Before an abrasive grinding wheel is mounted, it should be:
- a.Inspected and ring-tested for cracks✓
- b.Dropped on the floor to test it during the earlier phases of work
- c.Soaked in a solvent bath
- d.Painted over any visible cracks
Under 29 CFR 1926.303, abrasive wheels must be inspected and ring-tested before mounting to detect cracks. A cracked wheel can shatter at speed, a severe struck-by hazard. The guard and proper speed rating are also verified.29 CFR 1926.303
Hand and power tools must be maintained in what condition?
- a.Broken but held together with tape
- b.With their guards removed for speed
- c.Any condition, as long as they power on as long as the tools look intact
- d.Safe condition, with damaged tools removed from service✓
Under 29 CFR 1926.300, all hand and power tools must be maintained in a safe condition, whether owned by the employer or the worker. Damaged tools are removed from service. Guards must be kept in place during use.29 CFR 1926.300
What is a key safety rule when using a powder-actuated tool?
- a.Point it at coworkers to check the aim
- b.Only trained, certified operators may use it, and not in explosive atmospheres✓
- c.Anyone may use it without any training
- d.Use it in flammable vapor for convenience for most residential-scale jobs according to older industry practice
Under 29 CFR 1926.302, powder-actuated tools may be operated only by trained, certified employees and must not be used in explosive or flammable atmospheres. The tool must be tested each day before use. Misfires and ricochets are serious struck-by hazards.29 CFR 1926.302
When a load is being hoisted overhead, workers on the ground should:
- a.Stand directly beneath to guide it by hand when only one worker is involved
- b.Sleep in the drop zone during breaks
- c.Sit under it to rest in the shade
- d.Stay clear and never stand under the suspended load✓
Workers must never stand under a suspended load because rigging can fail, a top struck-by hazard. Under 29 CFR 1926.1425, workers are kept out of the fall zone except for limited tasks. Tag lines control the load from a safe distance.29 CFR 1926.1425
Which is required for emergency-response readiness on many construction sites?
- a.Only a suggestion box for workers
- b.A single phone with no numbers posted under most routine jobsite conditions
- c.No emergency planning is necessary
- d.A way to summon aid and trained first-aid providers or nearby medical care✓
Under 29 CFR 1926.50, employers must ensure medical personnel are available for advice and that first-aid providers or nearby clinics respond when no infirmary is close. Emergency numbers must be posted. Prompt care reduces injury severity.29 CFR 1926.50
When must eyewash or quick-drenching facilities be provided?
- a.Where workers may be exposed to injurious corrosive materials✓
- b.Never on any construction site
- c.Only inside office break rooms
- d.Only for occasional site visitors as some contractors interpret the rule
Under 29 CFR 1926.50(g), suitable facilities for quick drenching or flushing of the eyes and body must be provided where workers may be exposed to injurious corrosive materials. They allow immediate rinsing after a splash. They must be within quick reach.29 CFR 1926.50(g)
Illumination must be provided in work areas so that:
- a.Energy is saved by working in the dark when the crew is short on time
- b.Workers can see hazards and perform tasks safely✓
- c.Only supervisors are able to see
- d.The site looks attractive at night
Under 29 CFR 1926.56, construction areas must have minimum illumination levels so workers can see to work and recognize hazards. Poor lighting contributes to slips, trips, and struck-by incidents. Different areas have different minimum foot-candle levels.29 CFR 1926.56
What should a competent person do upon finding a hazardous condition in a trench?
- a.Add more spoil onto the trench edge
- b.Tell the workers to dig much faster
- c.Do nothing until the following month according to older industry practice
- d.Remove workers from the trench until it is corrected✓
Under 29 CFR 1926.651(k), when a competent person finds evidence of a possible cave-in, hazardous atmosphere, or other hazard, exposed workers must be removed until precautions are taken. Worker removal is immediate. Inspection has no value without action.29 CFR 1926.651(k)
When could a hazardous atmosphere require testing in an excavation?
- a.Only in trenches over 100 feet deep
- b.Only when the excavation is indoors
- c.Never, since trenches are open to air unless a supervisor decides otherwise
- d.In excavations over 4 feet deep where such an atmosphere could exist✓
Under 29 CFR 1926.651(g), atmospheres in excavations more than 4 feet deep must be tested where oxygen deficiency or hazardous atmospheres could exist, such as near landfills or where gases could enter. Ventilation and controls follow if needed. Heavier-than-air gases can pool in trenches.29 CFR 1926.651(g)
Which is a materials-handling control when using a powered industrial truck (forklift)?
- a.Give coworkers rides on the raised forks
- b.Let untrained workers operate the truck
- c.Do not exceed the rated capacity and keep the load low while traveling✓
- d.Carry loads as high as possible while driving for the majority of standard tasks
Powered industrial trucks must be operated within their rated capacity by trained operators, with loads carried low and tilted back. Under 29 CFR 1926.602, operators must be trained. Overloading and raised loads cause tip-overs and struck-by injuries.29 CFR 1926.602
Why must aisles and passageways be kept clear where mechanical handling equipment is used?
- a.To deliberately slow down the work
- b.To make the busy site look tidy
- c.To provide safe clearance and prevent struck-by and caught-between incidents✓
- d.To create room to store extra pallets based on the project's own schedule for typical light-duty operations
Under 29 CFR 1926.250, aisles and passageways must be kept clear and in good repair, with sufficient safe clearance where mechanical handling equipment operates. Blocked aisles force workers into the path of equipment. Clear routes reduce struck-by and caught-between risk.29 CFR 1926.250
A load chart on a crane provides which critical information?
- a.The available paint color options
- b.The current fuel price for the day
- c.The rated lifting capacity at various boom lengths and radii✓
- d.The operator's daily work schedule in the absence of a written program
The load chart shows the crane's rated capacity for different configurations of boom length, radius, and outrigger position. Operators must never exceed these values, per 29 CFR 1926.1417. Exceeding capacity leads to tip-overs and structural failure.29 CFR 1926.1417