OSHA 30 Construction — All Questions

Where a construction receptacle lacks built-in GFCI protection, an acceptable option is to:

• a.Remove the tool's grounding prong so it will fit the receptacle
• b.Wrap the plug connection in electrical tape to seal out moisture instead
• c.Use a listed portable (plug-in) GFCI ahead of the tool✓
• d.Simply proceed without protection because the tool is double-insulated

A listed portable, plug-in GFCI can be inserted between a non-GFCI receptacle and the tool to provide the ground-fault protection required by 29 CFR 1926.404(b)(1). It offers the same fast shock protection as a permanent GFCI. It must be tested before use like any GFCI.

What is a 'short circuit' in an electrical system?

• a.An unintended low-resistance path that allows excessive current to flow✓
• b.A circuit that has simply been made physically shorter in length
• c.The normal path electricity takes when a tool is working correctly
• d.A path of very high resistance that gradually reduces current flow

A short circuit is an unintended, low-resistance connection between conductors that allows a large current to flow, which can cause overheating, arcing, and fire if overcurrent protection does not clear it. Fuses and breakers under 29 CFR 1926.404(e) are sized to interrupt this current. It differs from a ground fault, which flows to ground.

Lockout devices used to control hazardous energy must be:

• a.Removable with an ordinary key that is kept in the site office drawer
• b.Made from whatever spare materials happen to be lying around the site
• c.Durable, standardized, substantial, and identifiable to the user✓
• d.Interchangeable so any worker can key open any other worker's lock

Effective lockout devices, per hazardous-energy control principles applied under 29 CFR 1926.417, must be durable enough for the environment, standardized by color/shape/size, substantial enough to prevent removal without excessive force, and identify the worker who applied them. A device anyone can open provides no protection. This ensures each lock is under one worker's control.

Why is 60-hertz alternating current (standard building power) particularly hazardous to the human body?

• a.It flows so slowly that a person always has time to let go safely
• b.It only heats wiring and never affects the human heart in any way
• c.It is completely harmless because alternating current cannot injure people
• d.It can disrupt the heart's rhythm and cause muscles to lock onto conductors✓

Standard 60-Hz AC can cause muscle tetany that prevents letting go of a conductor and can trigger ventricular fibrillation of the heart at relatively low currents. These physiological effects make ordinary building power deadly. GFCI protection under 29 CFR 1926.404(b)(1) limits the current and duration of exposure.

The grounding electrode system (such as a ground rod) in an electrical installation serves to:

• a.Carry the normal operating current that powers all the connected tools
• b.Store electricity so the site has backup power during an outage
• c.Insulate the building's wiring from the surrounding soil and moisture
• d.Connect the system to earth to help stabilize voltage and clear faults✓

The grounding electrode system connects the electrical system to earth, stabilizing voltage relative to ground and helping fault current return to operate protective devices, as part of grounding requirements in 29 CFR 1926.404(f). It is not the normal load-current path. Proper grounding is essential to shock and fire protection.

An extension cord that must run across a walkway or roadway should be:

• a.Laid loosely across the path so vehicles can compress it flat
• b.Protected from damage, for example elevated or covered by a cord ramp✓
• c.Left uncovered because cords are strong enough to be driven over
• d.Coiled tightly in the middle of the walkway to keep it out of the dirt

Cords crossing walkways or vehicle paths must be protected from damage, such as by elevating them or using cord protectors/ramps, to prevent insulation damage and trip hazards, consistent with 29 CFR 1926.416(e) and 1926.405. Damaged insulation creates shock and fire risk. Cords should be routed to avoid traffic where possible.

Before re-energizing equipment at the completion of lockout/tagout, workers must:

• a.Leave the guards off so the next crew can inspect the machine easily
• b.Start the equipment quickly to save time before anyone can object
• c.Assume everyone is clear without checking the work area at all
• d.Ensure all guards are replaced and every worker is clear of the equipment✓

The final steps of hazardous-energy control require replacing guards, verifying tools are removed, confirming all workers are safely clear, and notifying affected employees before removing locks and re-energizing, consistent with 29 CFR 1926.417. Skipping these checks can injure someone still working on the equipment. Only then may power be restored.

Weatherproof covers and enclosures on receptacles and connections in outdoor or wet locations are required to:

• a.Improve the appearance of the temporary power system for inspections
• b.Keep moisture out so the connection does not fault or shock a worker✓
• c.Keep the connection warm enough to conduct electricity in cold weather
• d.Reduce the amount of cord needed to reach across the job site

In damp and wet locations, receptacles and connections must have weatherproof enclosures or covers to keep out moisture that could cause ground faults and shock, per 29 CFR 1926.405 and 1926.404(f). Wet connections greatly increase shock severity. Keeping connections up off wet ground and covered is a basic control.

On a GHS label, the exclamation-mark pictogram generally warns of:

• a.A powerful explosive capable of detonating from a small spark
• b.A gas stored under extremely high pressure inside a sealed cylinder
• c.Acute toxicity severe enough to cause death from a brief exposure
• d.Less severe hazards such as skin or eye irritation✓

Under 29 CFR 1910.1200, the exclamation-mark pictogram covers less severe hazards, including skin and eye irritation, skin sensitization, and acute toxicity of lower categories. It is distinct from the skull-and-crossbones (acute toxicity, severe) and the health-hazard pictograms. Reading the hazard statements clarifies the specific concern.

Which safety data sheet section identifies the hazards of the chemical, including its classification?

• a.Section 2✓
• b.Hazard information is not included on the safety data sheet at all
• c.Section 9, which lists physical and chemical properties only
• d.Section 13, which addresses disposal considerations for the product

In the 16-section SDS format required by 29 CFR 1910.1200, Section 2 is hazard identification, including the GHS classification, signal word, hazard statements, and pictograms. Workers use it to understand the dangers before handling the chemical. Section 4 covers first aid and Section 8 covers exposure controls.

Which safety data sheet section covers safe handling and storage of a chemical?

• a.Section 5, which addresses firefighting measures for the product
• b.Section 11, which presents detailed toxicological information only
• c.Section 7✓
• d.Handling and storage guidance never appears on a safety data sheet

In the standardized SDS format under 29 CFR 1910.1200, Section 7 covers handling and storage, including precautions for safe handling and conditions for safe storage such as incompatibilities. It helps workers store and use chemicals without triggering reactions. Section 6 addresses accidental release (spills).

Air-purifying respirator cartridges and filters must be:

• a.Selected for the specific contaminant and changed on a proper schedule✓
• b.Kept in service indefinitely because cartridges never lose effectiveness
• c.Chosen at random since all cartridges protect against all chemicals
• d.Used until they visibly fall apart, regardless of what they filter

Under 29 CFR 1910.134, cartridges and filters must be matched to the specific contaminant and replaced based on an end-of-service-life indicator or a change schedule, because a saturated cartridge stops protecting. A gas cartridge does not stop particulates, and vice versa. Correct selection is part of the respiratory protection program.

Housekeeping under the silica standard prohibits which practices when cleaning up dust?

• a.Using a HEPA-filtered vacuum to collect the settled silica dust
• b.Dry sweeping and using compressed air where safer methods are feasible✓
• c.Wetting the dust down before carefully cleaning it up by hand
• d.Sealing collected silica waste in a labeled, closed container

29 CFR 1926.1153 prohibits dry sweeping, dry brushing, and using compressed air to clean surfaces or clothing where such actions could contribute to silica exposure and a feasible alternative exists. Wet methods and HEPA-filtered vacuuming are used instead. Good housekeeping keeps settled dust from becoming airborne again.

Under the construction lead standard, a worker is medically removed from lead exposure when their blood lead level reaches at least:

• a.500 micrograms per deciliter measured on a single random test
• b.There is no blood lead level that triggers medical removal at all
• c.50 micrograms per deciliter✓
• d.5 micrograms per deciliter, which is far below the removal trigger

29 CFR 1926.62 requires temporary medical removal when an employee's blood lead level is at or above 50 ug/dL (based on required testing), with return generally when it falls below 40 ug/dL. Medical removal protection maintains the worker's pay and benefits. Blood-lead monitoring detects overexposure so removal can occur before serious harm.

The Noise Reduction Rating (NRR) marked on hearing protectors indicates:

• a.The maximum noise level that is safe without any protection at all
• b.The price category of the earplug or earmuff being purchased
• c.The amount of noise attenuation the device can provide✓
• d.The number of years the hearing protector is guaranteed to last

The Noise Reduction Rating is a laboratory measure of how much a hearing protector reduces noise reaching the ear, helping match protection to the exposure controlled under 29 CFR 1926.101. Real-world attenuation is usually less than the labeled NRR. Protectors must be properly fitted to achieve their rated reduction.

The entry supervisor for a permit-required confined space is responsible for:

• a.Authorizing entry, verifying conditions, and terminating entry when needed✓
• b.Handling only the payroll paperwork while the entry takes place
• c.Working inside the space alongside the entrants for the whole shift
• d.Leaving the site as soon as the permit has been signed and posted

Under 29 CFR 1926.1209/1210, the entry supervisor authorizes entry, signs the permit, verifies that tests and controls are in place and acceptable conditions exist, and terminates the entry and cancels the permit when work is done or a hazard arises. The supervisor coordinates with the attendant and entrants. This oversight helps prevent unsafe entries.

Where feasible, non-entry rescue from a permit-required confined space is accomplished using:

• a.Waiting outside until the entrant is able to climb out on their own
• b.Coworkers rushing in without any equipment to pull the entrant out
• c.A retrieval line attached to a full-body harness and a mechanical device✓
• d.A single rope tied around the entrant's wrist with no anchor point

29 CFR 1926.1211 requires that a retrieval system (a full-body harness with a retrieval line and, for vertical spaces over 5 feet, a mechanical retrieving device) be used for non-entry rescue unless it would increase the risk or not help. Non-entry rescue avoids sending rescuers into the hazard. Most confined-space deaths involve untrained would-be rescuers.

Looking at a welding arc without proper eye protection can cause 'arc eye' (welder's flash), which is:

• a.A permanent improvement in the welder's ability to see in the dark
• b.A hearing problem caused by the loud noise of the welding equipment
• c.A harmless flash of color that fades within a few seconds every time
• d.A painful burn of the eye's surface from intense ultraviolet light✓

The intense ultraviolet and visible light from a welding arc can cause photokeratitis ('arc eye' or welder's flash), a painful, temporary burn of the cornea, and repeated exposure risks lasting damage. Filtered lenses and face protection are required under 29 CFR 1926.102 and the nonionizing radiation rule 1926.54. Bystanders must also be shielded from the arc.

Abrasive blasting and surface preparation on masonry or coated steel can expose workers to:

• a.Nothing hazardous, because blasting only produces harmless clean air
• b.Airborne silica or toxic metal dust requiring ventilation and respirators✓
• c.Only loud noise, with no airborne dust or metal fume generated at all
• d.A pleasant mist that improves air quality in the immediate work area

Abrasive blasting generates high levels of airborne dust that may contain crystalline silica or toxic metals (such as lead), requiring controls under 29 CFR 1926.55, 1926.1153, and 1926.62, including ventilation, containment, and respiratory protection. Blasting media itself can also be hazardous. Air-supplied respirators are often needed for blasters.

An inert gas such as nitrogen or argon is dangerous in a confined space mainly because it can:

• a.Catch fire spontaneously the moment it enters the confined space
• b.Displace oxygen and cause rapid asphyxiation without warning✓
• c.Add extra oxygen and make the air far healthier to breathe
• d.Produce a strong odor that clearly warns workers to leave the space

Inert gases like nitrogen and argon are not toxic but can displace breathable air, dropping oxygen below 19.5 percent and causing sudden collapse and death with no warning, a hazard controlled by atmospheric testing under 29 CFR 1926.1204. Purging or welding shielding gases can create this condition. Testing and ventilation are essential before and during entry.