PPE, Safe Setup and Work Practices: Lesson Test

Answer: D

Correct answer: The hazards identified for that particular task. PPE selection begins with a hazard assessment: look at what the job can actually do to the worker, such as flying chips, chemical splash, hot metal, sharp edges or noise, then choose equipment rated for those exposures and sized to fit. The tempting shortcut is one standard kit or the priciest gear, but protection works only when it matches the specific hazard; an expensive leather glove, for example, offers little against a solvent.

• A: Price alone does not establish protection against the relevant hazard.
• B: Convenience says nothing about compatibility with the assessed task.
• C: Different hazards require different types and ratings of protection.
• D (correct): PPE must correspond to the actual impact, splash, heat, cut, or other exposure and fit the worker.

Answer: B

Correct answer: To protect the eyes from impact by particles. Cutting and grinding throw chips and fragments at high speed, and the surface of the eye is easily scratched or penetrated, so even a tiny particle can cause lasting damage. Impact-rated safety eyewear, marked to the ANSI Z87.1 standard, is built to stop that energy. A common misconception is that a machine guard makes eyewear unnecessary; guards block much of the debris, but chips can still escape around them.

• A: Protective eyewear has no cutting-edge maintenance function.
• B (correct): Flying fragments can strike the eye even during short operations.
• C: Eyewear has no effect on the electrical load drawn by a motor.
• D: Eye protection complements a cutter guard but does not replace it.

Answer: A

Correct answer: A suitable clamp or vise. When a drill bit grabs the work, especially as it breaks through thin stock, it can whip the workpiece around with the full torque of the spindle. A clamp or drill-press vise transfers that load to the machine table instead of to the operator's hand. Small parts are the riskiest to hand-hold because there is little to grip and fingers end up close to the bit; a rag or glove only adds an entanglement hazard.

• A (correct): A fixture restrains stock against rotation or movement while keeping hands clear.
• B: Loose fabric can entangle and cannot safely resist drilling torque.
• C: Sunglasses neither restrain work nor provide an approved gripping fixture.
• D: A label informs a worker but does not physically hold material.

Answer: A

Correct answer: Keep the operator away from hazardous moving parts. A pinch point, or in-running nip, forms where two parts rotate toward each other, such as meshing gears or a belt meeting a pulley, and it pulls in anything that touches it. A guard is an engineering control: it physically blocks hands, hair and clothing from reaching the nip, so safety does not depend on constant attention. Training and warning signs help, but they cannot stop a slip the way a barrier can.

• A (correct): Physical guarding can prevent entry into the dangerous in-running nip.
• B: Workers still need training in setup, hazards and safe use even when guards are installed.
• C: Guards do not provide dimension measurements.
• D: A guard is a physical barrier, not a speed-control or power adjustment.

Answer: D

Correct answer: Protect the area and use the approved cleanup procedure. Oil on a walkway is a slip hazard that persists until it is removed, so the first step is to warn people or block off the area. Then follow the shop's method, typically an absorbent suited to the oil, followed by proper disposal of the used material. Covering the spill or walking around it only hides the hazard, and blowing it with air spreads the slick over a larger area.

• A: The hazard remains for coworkers and visitors.
• B: A makeshift cover does not restore a safe walking surface.
• C: Compressed air spreads material and can create additional hazards.
• D (correct): Prompt hazard control and proper cleanup reduce slipping and exposure.

Answer: B

Correct answer: Chemical hazard and safe-handling information. Under OSHA's Hazard Communication Standard, each hazardous chemical has a safety data sheet in a standard 16-section format covering identification, hazards, first aid, firefighting, handling and storage, and exposure controls and PPE, among other topics. The container label gives a quick summary at the point of use, while the SDS is the detailed reference. A common misunderstanding is that one replaces the other; the two work together, and the SDS often adds PPE requirements rather than waiving them.

• A: A document does not cancel appropriate protection.
• B (correct): The safety data sheet covers hazards, controls, first aid, and other use information.
• C: Hazard communication uses both labeling and safety data sheets.
• D: Drill dimensions are not the primary purpose of a chemical SDS.

Answer: C

Correct answer: To reduce the risk of hair being caught by moving parts. A rotating spindle, chuck or shaft winds up anything that touches it, and hair can be pulled in faster than a person can react, causing severe scalp injuries. Tying long hair back and covering it with a cap removes the loose material. The same reasoning applies to loose sleeves, jewelry and gloves near rotating equipment. Guards reduce exposure but do not make hair control optional.

• A: Surface finish depends on the tool, material, settings and workholding, not on the operator's hair.
• B: Hair control does not supply a physical machine guard.
• C (correct): Rotating spindles and shafts may entangle long hair rapidly.
• D: Hair restraint cannot change the mechanical spindle speed.

Answer: A

Correct answer: Supplements appropriate eye protection for the hazard. Eye-protection standards treat a face shield as a secondary protector: it shields the face from sparks and fragments, but it is open at the bottom and sides, so particles can still reach the eyes from below or around the edges. That is why safety glasses or goggles are worn underneath it. The tempting mistake is to treat the larger shield as a replacement for eyewear, when it is designed only as an added layer.

• A (correct): A face shield may protect additional facial area while eyewear remains necessary.
• B: A face shield alone may leave eyes vulnerable and need supplementary eyewear.
• C: The wheel needs the required guarding regardless of personal equipment.
• D: Protection worn by a person cannot ensure wheel mechanical integrity.

Answer: A

Correct answer: Remove it from service and report it. A crack concentrates stress, so the handle can snap suddenly under a load it carried easily before, driving the hand into the work or sending the tool head flying. Taking the tool out of use and tagging or reporting it ensures nobody else picks it up before it is repaired or replaced. Taping or wrapping the handle only hides the damage, and pushing harder raises the very load that causes failure.

• A (correct): A cracked handle can fail without warning during normal tool loading.
• B: Higher force makes a failed handle more dangerous.
• C: Paper does not restore structural integrity.
• D: Altering unrelated safeguards adds risk and does not repair the handle.

Answer: C

Correct answer: The location where its blade performs the cutting work. OSHA defines the point of operation as the area on a machine where work is actually performed on the material, such as cutting, shaping, boring or forming. Because this is where the blade meets the stock and hands guide the work, it is usually the most dangerous spot and must be guarded. Do not confuse it with power-transmission parts like belts and pulleys, which are separate hazards with their own guards.

• A: A record station has no relationship to the active cutting point.
• B: The plate identifies the equipment but is not the zone where cutting takes place.
• C (correct): The point of operation is where the tool acts on the material.
• D: An exit is not the location of tool-material processing.

Answer: C

Correct answer: They seal closer around the eyes to guard against liquid splashes. Ordinary safety glasses are built to stop flying solid particles, but they leave gaps at the top, sides and bottom where a splashed liquid can run in. Chemical-splash goggles fit against the face and usually have indirect vents or none, so droplets have no straight path to the eye. They protect only the eyes, though; a face shield may be added for the face, and vapors call for separate respiratory controls.

• A: Eye protection does not filter the surrounding atmosphere.
• B: Goggles protect only the eyes; breathing hazards require separate respiratory protection.
• C (correct): Splash goggles enclose the eyes, and their chemical rating must match the liquid-exposure hazard.
• D: PPE does not change the substance chemical properties.

Answer: D

Correct answer: The gloves can be captured and draw a hand into the rotation. A spinning spindle or chuck grips anything loose that touches it, and glove material is often strong enough to keep pulling rather than tear free, so the hand follows the glove into the machine in a fraction of a second. That is why shops generally prohibit gloves near exposed rotating parts, the same reasoning applied to loose sleeves and long hair. The misconception is that gloves always add protection; here they create the hazard.

• A: Hand protection does not replace correct workholding.
• B: Glove use does not control motor output torque.
• C: Work gloves do not change the magnetic properties of steel.
• D (correct): Loose material can entangle rapidly near exposed spinning components.

Answer: B

Correct answer: An emergency stop may halt motion without isolating every energy source. An emergency stop is a control command meant to bring motion to a quick halt; the power supply may still be connected, and someone could reset it or a fault could restart the machine. Lockout uses an energy-isolating device, such as a disconnect or valve, physically secured with a personal lock, followed by release of stored energy and a verification check. That is why an emergency stop is never a substitute for lockout during servicing.

• A: Lockout controls hazardous energy rather than chemical labeling.
• B (correct): Energy isolation and verification address restart and stored-energy hazards.
• C: Stopping normal operation is not the same as energy isolation.
• D: A stop button is not necessarily a positive energy-isolating device.

Answer: C

Correct answer: One-eighth inch. On an offhand grinder, the operator steadies the workpiece on the work rest while pressing it against the wheel. If the gap between rest and wheel is too wide, a small part or a finger can be dragged into it and wedged, which can break the wheel or injure the hand. OSHA therefore requires the rest to be kept adjusted closely, no more than 1/8 inch away, readjusting as the wheel wears. Do not confuse this with the 1/4-inch limit for the upper tongue guard.

• A: That clearance would exceed the cited work-rest maximum.
• B: One-quarter inch applies to certain adjustable upper tongue-guard gaps, not this rest.
• C (correct): The work-rest limit is 1/8 inch to reduce work jamming near the abrasive wheel.
• D: A large opening greatly increases the chance of trapping work.

Answer: A

Correct answer: A maximum of one-quarter inch. The tongue guard is the adjustable piece at the top of the wheel opening in the grinder's hood. As the wheel wears and shrinks, the gap at the top grows, so the tongue guard must be readjusted to keep the opening at or below 1/4 inch, helping contain fragments if the wheel breaks. A handy memory aid: rest 1/8 inch, tongue 1/4 inch. PPE such as a face shield adds protection but never waives either limit.

• A (correct): The upper tongue-guard clearance is distinct from the work-rest limit.
• B: These two devices have different OSHA numerical limits.
• C: PPE does not waive a guarding clearance requirement.
• D: The OSHA rule gives a maximum near the wheel, not a large minimum.

Answer: C

Correct answer: Stop use and have it repaired through authorized procedures. Insulation is what keeps current inside the conductors; once it is broken, touching the plug while it is energized can send current through the body, and a damaged plug may also lose the ground connection that protects against faults. A tool that still runs proves only that the circuit is complete, not that it is safe. The tool should be unplugged, tagged out of service and repaired or replaced by a qualified person.

• A: Water may worsen electrical exposure and create slipping hazards.
• B: Motor and switch operation do not prove that exposed conductors are safe to touch.
• C (correct): Damaged insulation or exposed conductors can cause shock, so the tool must be taken out of use and properly repaired.
• D: A rag does not repair conductor insulation or plug integrity.

Answer: A

Correct answer: Hands may contact sharp chips or rotating tooling. Drilling chips are thin, hot and razor-edged, and long stringy chips often wrap around the bit, so reaching for them brings the hand into the rotating zone, where the chip itself can pull the hand in. The safe approach is to stop the spindle, let it come to rest, and then clear chips with a brush, hook or pliers. A glove is not a fix, since it can be snagged and drawn into the rotation.

• A (correct): Wait for safe machine condition and use an appropriate chip-removal tool.
• B: Color perception is not the relevant hazard.
• C: Ordinary machining chips are not inherently radioactive.
• D: Gloves may themselves increase entanglement risks around moving parts.

Answer: B

Correct answer: An eight-hour time-weighted average requiring a hearing conservation program. OSHA averages a worker's noise exposure over a full shift rather than judging single loud moments. When that eight-hour average reaches 85 dBA, the employer must run a hearing conservation program, including exposure monitoring, annual audiograms, training and available hearing protectors. The permissible exposure limit is higher, 90 dBA, and the allowed time halves for every 5 dB increase. The trap is reading 85 as a per-tool rating or an instant ceiling.

• A: It is an exposure criterion, not a universal tool-performance rating.
• B (correct): The action level concerns a measured time-weighted worker exposure.
• C: Impulse or impact noise is addressed separately, with a 140 dB peak guideline, not by the 85 dBA action level.
• D: Instantaneous and duration-dependent effects cannot be simplified this way.

Answer: D

Correct answer: An air-purifying respirator filters air but does not supply oxygen. Filters and cartridges clean the surrounding air as the wearer breathes it in, so they work only when that air has enough oxygen and the contaminant is known and within what the cartridge can handle. Supplied-air respirators deliver clean breathing air from a separate source through a hose, and self-contained units carry their own tank. That is why an oxygen-deficient atmosphere calls for supplied air, never a filter mask.

• A: Color is not a sufficient basis for respiratory safety selection.
• B: Respiratory and eye protection are distinct equipment categories.
• C: Filtration does not manufacture an oxygen supply.
• D (correct): Respirator selection must account for atmosphere and contaminant conditions.

Answer: C

Correct answer: Chemical compatibility and expected exposure conditions. Solvents can permeate glove materials at the molecular level, passing through without visible holes, and each material resists different chemicals: nitrile handles many oils and some solvents, while butyl or Viton suit chemicals that degrade nitrile. Manufacturer compatibility charts list breakthrough times, which must be matched to how long and how heavily the hands will be exposed. Fit and comfort matter too, but only after the material is chemically suitable.

• A: Individual fit alone does not establish chemical resistance.
• B: Cut resistance is not the same as resistance to solvent permeation.
• C (correct): The glove must resist the actual substance and contact time as assessed.
• D: Color is not reliable chemical compatibility evidence.

Answer: C

Correct answer: A properly designed and maintained barrier guard. Safety professionals rank controls in a hierarchy: eliminating or physically guarding a hazard comes before warnings, procedures and PPE, because a barrier works whether or not someone is paying attention. A belt-and-pulley nip pulls in fingers or clothing faster than a person can react, so only a barrier that keeps body parts out of reach reliably prevents contact. Signs and verbal reminders depend on human memory and have no physical effect.

• A: A sign informs workers but does not act as a physical barrier.
• B: Hearing protection does not control mechanical contact.
• C (correct): Physical separation prevents workers reaching moving in-running points.
• D: A spoken reminder cannot stop a hand from contacting a nip.

Answer: B

Correct answer: It can disperse particles and create new exposure or ignition hazards. Blowing dust does not remove it; it lifts fine particles into the air, where workers breathe them, and moves them onto ledges, machines and other surfaces. Combustible dust such as wood, metal or plastic particles can even form a cloud that ignites. Capturing methods, like a vacuum suited to the material or wet sweeping, collect dust instead of relocating it. The misconception is that a clean-looking floor means the hazard is gone.

• A: Cleaning air has no structural strengthening effect.
• B (correct): Use an approved cleanup method compatible with the material and controls.
• C: Dispersing material is not equivalent to capturing or removing it.
• D: Air pressure does not neutralize dust; the material keeps its hazards wherever it settles.

Answer: B

Correct answer: Reduced below 30 psi and used with effective chip guarding and PPE. The rule targets two dangers: high-pressure air can propel chips into the eyes or skin, and air forced against the body can enter tissue or the bloodstream. Limiting the dead-end pressure to under 30 psi reduces that force, while chip guarding and personal protective equipment handle what still flies. A frequent misreading is that low pressure alone makes cleaning compliant; all three conditions are required together.

• A: Compressed air should not be directed at the body.
• B (correct): The pressure condition is only one of several requirements for permissible cleaning.
• C: The OSHA exception also requires guarding and PPE.
• D: High pressure increases flying-particle hazards and does not meet the cited cleaning provision.

Answer: A

Correct answer: Physically holds an energy-isolating device in a safe position. A tag is only a warning; anyone can ignore it or flip the switch beneath it. A lock is fitted through the disconnect, valve or breaker so the device cannot be moved to the on position without the key, which the authorized worker keeps. That is why OSHA prefers lockout whenever the isolator can accept a lock. Neither method removes the need to release stored energy and verify isolation.

• A (correct): A lock provides a positive restraint against normal operation.
• B: A lock has no measurement function.
• C: Authorized employees must still verify isolation before covered work, whether a lock or a tag is used.
• D: Stored energy still needs to be identified and controlled.

Answer: C

Correct answer: A compressed spring that could move a machine slide. Switching off a motor stops new energy from entering, but energy already stored in the machine can remain: compressed springs, raised parts held up against gravity, pressurized hydraulic or air lines, charged capacitors and coasting flywheels. Lockout procedures therefore include releasing, blocking or bleeding this residual energy before work begins. The tempting assumption is that a quiet machine is safe; a stored-energy source can still move parts with no power applied.

• A: Paperwork cannot itself produce hazardous mechanical motion.
• B: A fully relaxed object is not the intended residual-energy case.
• C (correct): Mechanical stored energy can release even with power disconnected.
• D: This does not describe an energized or stored-force machine component.

Answer: D

Correct answer: To prevent unexpected spinning or displacement if the bit catches. When a drill bit grabs, often as it breaks through the far side of the material, spindle torque transfers to the workpiece and can spin it like a blade. Clamping the work to the table or holding it in a drill-press vise lets the machine absorb that force instead of the operator's hand. Clamping does not stop chips or replace eye protection; it controls workpiece movement only.

• A: Workholding and electrical protection handle different hazards.
• B: Clamps do not stop all chip or particle hazards.
• C: Clamping the material does not stop the spindle.
• D (correct): Positive workholding controls movement and keeps hands from the bit.

Answer: D

Correct answer: A guard changes access to the hazard; PPE protects the exposed wearer. Engineering controls change the workplace itself, for example by enclosing a moving part or ventilating fumes, so they protect everyone nearby without depending on behavior. PPE leaves the hazard in place and puts a barrier on one person, so it works only if that person wears the right item correctly. That is why PPE sits near the bottom of the hierarchy of controls and is often called the last line of defense.

• A: Guards are preventive physical controls.
• B: PPE does not remove contaminants from the air; it only protects the person wearing it.
• C: Guards and PPE provide protection beyond visual warning.
• D (correct): The controls operate at different stages of hazard management.

Answer: B

Correct answer: Do not run the machine until the required guard is restored. An abrasive wheel spins at high speed, and if it breaks, the guard is what contains the fragments and directs them away from the operator. Without it, pieces can fly out with enough energy to cause serious or fatal injuries. The right action is to keep the grinder out of service and report it. PPE such as a face shield helps against sparks and small particles but cannot stop a bursting wheel.

• A: The operator remains exposed even when the area is empty.
• B (correct): A face shield or caution is not a substitute for required machine guarding.
• C: Higher speed may increase the severity of wheel failure.
• D: Unrated glasses cannot replace missing machinery protection.

Answer: D

Correct answer: Identify the substance through proper labeling and workplace procedures. Many hazardous liquids look like water, so appearance and smell give no reliable information. The safe sequence is to leave the bottle alone, report it to a supervisor, and identify it through records or the matching safety data sheet; if it cannot be identified, it is handled as hazardous. Mixing or testing unknowns is especially dangerous: bleach combined with an ammonia cleaner, for example, releases toxic chloramine gas.

• A: Deliberate sniffing can create inhalation exposure, and many hazardous chemicals have no warning odor.
• B: Skin testing is unsafe and inappropriate.
• C: Mixing unknown chemicals can create dangerous reactions.
• D (correct): An unknown liquid must not be treated as harmless from its appearance.

Answer: C

Correct answer: To support a prompt, coordinated response if danger occurs. In an emergency such as an entanglement, fire or chemical release, the seconds spent searching for a stop button or exit can decide how bad the injury is. Knowing these locations beforehand turns the response into a reflex rather than a search. This planning does not replace prevention: guards, PPE and safe setup reduce the chance of an emergency, while preparedness limits the harm when one occurs.

• A: Emergency information does not waive prevention requirements.
• B: The effectiveness of PPE is not defined by proximity to a door.
• C (correct): Emergency planning complements preventive controls and safe work setup.
• D: Emergency locations have nothing to do with speed transmission or gear ratios.

Answer: A

Correct answer: It exceeds the 0.125-inch maximum and must be corrected before use. Convert fractions to decimals to compare: 1/8 inch = 0.125 inch and 3/16 inch = 0.1875 inch, so the gap is 0.0625 inch, or 1/16 inch, too wide. The rest must be moved closer to the wheel, a routine adjustment as wheels wear down. The tempting error is measuring against 0.25 inch, but that limit belongs to the upper tongue guard, not the work rest.

• A (correct): Three-sixteenths exceeds one-eighth by 0.0625 inch.
• B: One-eighth is 0.125 rather than 0.1875 inch.
• C: PPE does not relax the rest-gap maximum.
• D: One-quarter inch is the upper tongue-guard limit; the work rest is held to one-eighth inch.

Answer: D

Correct answer: The upper guard gap is too large even though the rest gap is acceptable. Check each clearance against its own limit. The work rest may be no more than 0.125 inch from the wheel, and 0.10 inch meets that. The upper tongue guard may be no more than 0.25 inch away, and 0.30 inch exceeds it by 0.05 inch, so the grinder needs adjustment before use. Passing one check does not clear the machine; every guarding requirement must be met at the same time.

• A: One-eighth is a maximum, not a minimum opening.
• B: No 0.50-inch limit applies; the rest and the upper guard have tighter, separate limits.
• C: Machine guarding requirements remain independently necessary.
• D (correct): 0.30 exceeds the 0.25-inch upper-tongue limit on applicable equipment.

Answer: D

Correct answer: Ten times as large. The decibel scale is logarithmic: level in dB = 10 × log10(I ÷ I0), so each 10 dB step multiplies intensity by 10, and a 20 dB step multiplies it by 100. Going from 80 to 90 dB is exactly one 10 dB step. A useful hook is that every 3 dB roughly doubles intensity. The trap is treating decibels like ordinary numbers and reading 90 ÷ 80 as only 12.5% more.

• A: This treats dB as an ordinary linear fraction.
• B: A 20 dB change gives a factor of 100 intensity.
• C: Approximately 3 dB, not 10 dB, corresponds to doubled intensity.
• D (correct): A 10 dB difference is a factor of 10 in intensity.

Answer: B

Correct answer: Control stored pressure and gravity loads, then verify isolation. Locking the disconnect only stops new electrical energy from reaching the press. Air can still be trapped in cylinders and lines, and a raised ram can drop under its own weight if pressure leaks off. So the worker bleeds the pneumatic system, blocks or supports the ram with safety blocks or pins, and then tries the controls to verify nothing moves. A silent motor proves nothing about these other energy sources.

• A: The ram might move from stored pressure or its own weight.
• B (correct): Electrical isolation alone may not render residual hydraulic, pneumatic or gravity forces safe.
• C: Repeated stop commands are not equivalent to isolating stored energy.
• D: Gloves cannot restrain a descending press mechanism.

Answer: A

Correct answer: The checklist completion rate is 80%, but it does not prove the shop safe. Divide passed items by total items, part over whole:

or 80%. That number describes how many boxes were checked, not how dangerous the remaining 9 failures are. A single missing guard or failed interlock can cause a serious injury no matter how high the overall score, so critical items must be fixed rather than treated as a small deduction from a grade.

• A (correct): 36 divided by 45 is 0.8, and critical hazards cannot be averaged away.
• B: A count of items is not an effectiveness measurement.
• C: Critical safety defects require correction regardless of aggregate score.
• D: That calculation reverses numerator and denominator.

Answer: B

Correct answer: 28 inches. Clear width is the open space a person can actually pass through, so any obstruction projecting into the aisle subtracts directly from it:

Read the word clear as usable; an obstruction takes space away and never adds to it. Signs or markings warn people about a narrowing but do not restore the lost width. Because exit routes must keep minimum widths, a projection can make an aisle noncompliant.

• A: Adding an obstruction increases the number but not the usable space.
• B (correct): Subtract 8 inches from the original clear width of 36 inches.
• C: A warning sign does not restore physically blocked clearance.
• D: Dividing the width by obstruction size is not how clearance is calculated.

Answer: B

Correct answer: Selection includes program procedures, medical evaluation and fit testing. A tight-fitting respirator works only if it seals to the face and the wearer can safely breathe through it. A medical evaluation checks that the added breathing resistance will not harm the worker, and a fit test, done before first use and at least annually, confirms that the specific model and size seals. The respirator must also be selected for the actual contaminant. A comfortable or tight feel is not proof of a seal.

• A: Air-purifying equipment does not generate breathing oxygen.
• B (correct): The respiratory standard requires multiple safeguards beyond buying a facepiece.
• C: Perceived tightness is not a fit test; tight-fitting respirators need a qualitative or quantitative fit test.
• D: The respirator must be appropriate for the contaminant and workplace.

Answer: A

Correct answer: Use the applicable lockout program unless a full-protection tagout approach is justified. When an energy-isolating device can accept a lock, OSHA requires lockout unless the employer can show that a tagout program gives full employee protection, meaning safety equal to a lock, usually through extra measures such as removing a fuse or blocking a control. A tag is only a warning and can be ignored or torn off. Jam clearing is a classic injury scenario because the worker reaches into the machine expecting it to stay still.

• A (correct): A tag alone does not physically restrain the device, and OSHA sets strict conditions.
• B: The required method depends on the energy-control standard and procedure.
• C: Stored energy or unexpected startup can persist even when an indicator light is off.
• D: A warning tag does not mechanically immobilize the isolator.

Answer: C

Correct answer: Use compatible splash protection and gloves with assessed ventilation or source controls. Start with the SDS: its hazard and exposure-control sections name the routes of exposure and the protective measures. Eye splash calls for chemical-splash goggles, sometimes with a face shield; skin contact calls for gloves made of a material rated for that solvent. Vapors are handled by ventilation or other source controls. Cotton absorbs solvent and holds it against the skin, and ordinary glasses leave gaps for splashes.

• A: Neither item is necessarily rated for the chemical hazards.
• B: Removing hazard information undermines safe handling and leaves workers unaware of the risk.
• C (correct): Both eye and skin exposure must be addressed using chemical-specific information.
• D: An ignition source can worsen fire and vapor hazards.

Answer: D

Correct answer: Wait for a full stop, follow the control procedure, and use a proper chip tool. A coasting cutter has no power applied but still carries enough momentum to cut deeply, and milling chips are sharp and often hot. Waiting until rotation stops removes the motion hazard; following the shop's procedure, which may include lockout, prevents restart; and a brush or chip hook keeps fingers off the edges. Heavy gloves are a trap here, since cutter teeth can snag the glove and pull the hand in.

• A: Directed compressed air can spread flying-chip exposure.
• B: Gloves do not remove contact and entanglement danger from a rotating cutter.
• C: Manual restraint by another person does not isolate machine energy and puts that person's hands at risk.
• D (correct): Residual motion and sharp chips must both be controlled before clearing.

Answer: A

Correct answer: Switch the parts-washing process to the water-based cleaner. Rank controls from most to least effective: elimination, substitution, engineering controls, administrative controls, then PPE. Replacing the solvent with a less hazardous cleaner that works equally well is substitution, so it outranks the exhaust hood (engineering), signs and time limits (administrative) and respirators (PPE).

• A (correct): Substitution replaces the hazardous material with a less hazardous one, which ranks above engineering, administrative and PPE controls.
• B: Source capture is a strong engineering control, but it still leaves the flammable solvent in use, so it ranks below substitution.
• C: Respirators are PPE, the last line of defense, and they protect only the wearer while the vapor hazard remains.
• D: Signs and time limits are administrative controls that depend on people following rules; they do not change the hazard.

Answer: B

Correct answer: Clear glasses do not filter the intense light from the arc. First identify the exposure: arc welding produces intense optical radiation and hot spatter that can reach assistants and bystanders. Ordinary clear safety glasses stop impact but are not a welding filter, so the helper needs a filter lens of the right shade or a welding screen between the helper and the arc.

• A: Impact-rated eyewear is often worn under a welding helmet; the problem is that it lacks a filter for the arc light.
• B (correct): Arc welding gives off intense optical radiation, so nearby workers need a suitable filter shade or a welding screen, not just clear lenses.
• C: Splash goggles seal against liquids but do not filter arc radiation, so they would not solve the actual hazard.
• D: Reflected light and sparks still reach a bystander, so turning away is not a substitute for proper filter protection or screening.

Answer: B

Correct answer: About 91 dB. Decibels are logarithmic. Doubling sound intensity adds about 3 dB, while a tenfold increase adds 10 dB.

• A: This doubles the decibel number itself, but decibels are logarithmic, so doubling intensity does not double the dB value.
• B (correct): Doubling the acoustic intensity adds about 3 dB, so 88 dB + 3 dB is about 91 dB.
• C: Adding 10 dB corresponds to a tenfold increase in intensity, not a doubling.
• D: Two identical sources produce more total sound intensity than one, so the level must rise above 88 dB.

Answer: C

Correct answer: An approved step ladder set on firm, clear footing. To reach high storage, use approved access equipment such as a ladder or step stool rated for the job, checked for condition and set on firm, clear footing. Carts, chairs and stacked boxes are not designed to hold a climbing person and can move or tip.

• A: A cart can roll out from under the worker; it is not designed as access equipment.
• B: Chairs, even with locked wheels, are not approved climbing equipment and can tip or swivel.
• C (correct): Approved access equipment on stable footing is designed to support a person working at height.
• D: Improvised stacks of boxes or crates are unstable and can shift or collapse under a person.

Answer: D

Correct answer: The work rest must be adjusted, but the tongue-guard gap is acceptable. Convert each fraction to a decimal and compare it with its own limit.

Work rest:

which is more than the 0.125-inch (1/8) maximum, so it must be adjusted using a safe shutdown. Tongue guard:

which is less than the 0.250-inch (1/4) maximum, so it is acceptable.

• A: This ignores that 5/32 inch (0.156 in.) is larger than the one-eighth-inch (0.125 in.) work-rest maximum.
• B: This swaps the two limits; the tongue guard allows up to one-quarter inch, and the rest allows only one-eighth inch.
• C: Only the rest gap is too large; 7/32 inch (0.219 in.) is less than the one-quarter-inch (0.250 in.) tongue-guard maximum.
• D (correct): 5/32 in. = 0.156 in. exceeds the 0.125 in. rest limit, while 7/32 in. = 0.219 in. is within the 0.250 in. tongue-guard limit.

Answer: C

Correct answer: Remove the chuck key from the chuck. A chuck key left in the chuck becomes a projectile when the spindle starts. Always remove the key and any other setup tools before startup, then check the guard and clamping.

• A: Loose gloves near a rotating chuck and bit create an entanglement hazard instead of preventing one.
• B: Speed should match the bit and the material; the highest setting is not automatically correct or safer.
• C (correct): A key left in the chuck can be flung out at high speed when the spindle starts turning.
• D: Leaving the key in place is exactly the hazard: it can be thrown from the chuck at startup.

Answer: A

Correct answer: When the plug stays under the technician's exclusive control during the work. OSHA allows unplugging as energy control for cord-and-plug-connected equipment only when unplugging removes the risk of unexpected startup and the servicing worker keeps exclusive control of the plug, for example by keeping it in hand or in view. This exception does not extend to large or hard-wired machines or to equipment with retained energy.

• A (correct): The exception applies only if unplugging controls unexpected startup and the plug remains in the servicing worker's exclusive control.
• B: A tag only warns; if the plug lies where others can reach it, someone could plug it back in.
• C: Turning off the switch does not disconnect the power source, and the switch could be bumped back on.
• D: Unplugging alone is not enough if other people can reconnect the plug in a shared area.

Answer: A

Correct answer: The pass rate is 95%, but the press must not run until the interlock is fixed. Pass rate = 38 / 40 x 100 = 95%. That percentage describes the checklist, not the safety of the press: a failed interlock on a critical safeguard means the press stays out of service until it is repaired.

• A (correct): 38 / 40 = 0.95 = 95%, and a failed critical safeguard stops work no matter how many other items passed.
• B: A completion percentage does not measure safety; a single failed safety interlock makes the machine unsafe to use.
• C: 5% is the failure rate (2 of 40), not the pass rate, and redoing the checklist does not fix the interlock.
• D: 38 is the number of items passed, not the percentage; 38 out of 40 is 95%.

Answer: C

Correct answer: 20 inches. Add the widths of all obstructions and subtract the total from the original clear width.

The better fix, of course, is to move the pallet and cart out of the travel path.

• A: This subtracts only the pallet (44 - 15) and forgets the cart on the other side.
• B: 24 inches is the total width blocked by the two obstructions, not the width left over.
• C (correct): Both obstructions reduce the width: 44 - (15 + 9) = 44 - 24 = 20 inches.
• D: This subtracts only the cart (44 - 9) and forgets the pallet.

Answer: D

Correct answer: Move or shield the combustibles and follow the hot-work procedure. Grinding sparks are an ignition source, and cardboard and oily rags are fuel. PPE protects only the wearer, so the setup must control both sides: move or shield the combustible materials, follow the approved hot-work procedure and keep suitable fire protection ready.

• A: The apron and eye protection protect the wearer but do nothing to stop sparks from igniting the cardboard and rags.
• B: A fan can carry sparks farther into the packaging and spread the fire risk instead of controlling it.
• C: Fire protection is needed, but it does not replace separating the ignition source from the fuel before work starts.
• D (correct): Removing or shielding the fuel and following the approved hot-work procedure controls both the sparks and what they could ignite.

Answer: D

Correct answer: Assess his noise exposure and provide hearing protection selected for the task. Noise hazard depends on sound level and exposure time, not on personal comfort. Ordinary earbuds are not a replacement for task-selected earplugs or earmuffs, so the right approach is an exposure assessment, properly fitted hearing protection where required and following the employer's hearing program.

• A: Consumer earbuds are not validated hearing protection and may even add sound of their own to the ear.
• B: How tolerable a noise feels does not show whether the exposure is hazardous; level and duration matter.
• C: Louder music adds sound energy to the ear and increases total noise exposure.
• D (correct): Hearing risk depends on sound level and duration, so exposure should be measured and suitable occupational hearing protection used where required.

Answer: A

Correct answer: Remove both before starting the lathe. Rotating chucks and workpieces can catch dangling or loose items such as jewelry, sleeves and hair. The control is to remove rings, chains and similar items before running the machine so nothing that could be caught enters the danger zone.

• A (correct): Rings and necklaces can be caught by rotating parts and pull a finger or the neck toward the machine.
• B: A loose glove near a rotating chuck is another entanglement hazard, not a fix for the ring.
• C: A tucked chain can still work loose; removing jewelry is the reliable control.
• D: Even a slow chuck can wind in a ring or chain faster than a person can react.

Answer: B

Correct answer: Notify others, shut down, isolate and lock, relieve stored pressure, verify, then service. A sound energy-control sequence is: prepare and notify affected workers, shut the machine down, isolate the energy sources, apply lockout devices, relieve or restrain stored energy such as hydraulic pressure, and verify isolation. Only after verification does the technician enter the danger zone.

• A: Verifying before isolating proves nothing, and stored hydraulic pressure is never relieved.
• B (correct): This follows the documented order: shut down, isolate, apply devices, control stored energy and verify before entering the danger zone.
• C: An emergency stop does not isolate energy, a tag alone does not physically prevent startup, and stored pressure remains.
• D: Stored pressure must be relieved and isolation verified before reaching in, not after the blade work is done.

Answer: B

Correct answer: To keep hands farther from the blade while controlling the work. On narrow rip cuts, a hand pushing the board would come close to the blade. A push stick or push block lets the operator keep control of the workpiece while holding the hand a safer distance away, and it supplements, rather than replaces, the blade guard.

• A: A push stick works together with the guard; it does not replace it.
• B (correct): A push stick lets the operator guide the board while keeping fingers out of the hazardous blade region.
• C: Its purpose is hand protection and control, not faster feeding.
• D: Setting the cut width is the job of the fence, not the push stick.