420 questions
Insulated hand tools used for electrical work are typically rated for what voltage?
- a.50,000 volts, matching high-voltage transmission line insulators
- b.Only the exact voltage of the utility service feeding the building
- c.Zero volts, because any rating printed on a tool is only a suggestion
- d.1000 volts✓
Insulated tools for electrical work are commonly rated and marked for 1000 volts AC, providing protection when working on or near energized low-voltage systems. They must be inspected for damage before use, since cracks defeat the insulation. Rated insulated tools support the safe work practices of 29 CFR 1926.416.
If a coworker's personal lock must be removed while that worker is absent, the correct procedure is to:
- a.Follow the documented removal procedure and make reasonable efforts to notify them✓
- b.Wait indefinitely, leaving the equipment locked out for weeks if necessary
- c.Cut the lock off immediately without telling anyone and start the equipment
- d.Have any available employee remove it since one lock is the same as another
Removal of another worker's lock requires a specific documented procedure: verifying the worker is not present, making reasonable efforts to contact them, and ensuring they know the lock was removed before returning to work. This protects against re-energizing while someone is still exposed, per hazardous-energy control practices under 29 CFR 1926.417. It is never done casually.
What color or marking scheme is used to identify equipment tested under an assured equipment grounding conductor program?
- a.A random assortment of stickers applied whenever a worker has spare time
- b.No marking at all, since testing records are kept only in the office files
- c.A warning label stating the equipment has failed and must not be used
- d.A consistent identifying mark showing the item passed its required test✓
29 CFR 1926.404(b)(1)(iii)(E) requires that equipment passing the assured grounding tests be identified by a durable marking, such as colored tape, so workers know it was tested and is safe to use. The marking system must be consistent on the site. Untested or failed equipment is removed from service.
Why should extension cords not be 'daisy-chained' (plugged one into another in long runs)?
- a.It is only a concern indoors and never matters on an outdoor job site
- b.Long chained runs cause voltage drop and overheating hazards✓
- c.Chaining cords is required by OSHA to reach distant parts of the site
- d.Connecting cords together permanently improves the ground connection
Chaining multiple cords increases resistance and voltage drop, causing tools to draw more current and the cords to overheat, a fire and equipment hazard. It also multiplies connection points where damage and moisture can enter. Proper cord sizing and temporary power distribution reduce the need, consistent with 29 CFR 1926.405 and 1926.416(e).
A written energized electrical work permit is generally required when:
- a.Cords and portable tools are being visually inspected before the shift starts
- b.Work must be done on parts that cannot be de-energized✓
- c.A worker simply walks past an electrical panel on the way to another area
- d.Any routine task is performed on equipment that is already shut off and locked
When de-energizing is infeasible and qualified persons must work on or near exposed energized parts, an energized electrical work permit documenting the justification, hazard analysis, and controls is required under NFPA 70E and supported by OSHA's 29 CFR 1926.416. It ensures the risk is evaluated and approved. Routine de-energized work does not need such a permit.
The grounding conductor in a properly wired tool provides:
- a.Extra torque to the tool by adding a second live conductor to the motor
- b.A backup source of electricity if the primary supply is interrupted
- c.A low-resistance fault path so protection can clear a fault✓
- d.The main current path that powers the motor during normal operation
The equipment grounding conductor carries fault current back to the source so an overcurrent device trips or a GFCI operates, rather than energizing the tool housing. It is not part of the normal operating current path. Its integrity is verified under the assured grounding program in 29 CFR 1926.404(b)(1)(iii).
Only which employees should reset a tripped circuit breaker or re-energize equipment after a fault?
- a.Whoever first notices that the equipment has stopped running
- b.Trained and authorized persons who have verified it is safe✓
- c.The newest crew member, as a way of gaining hands-on experience quickly
- d.Any worker on site who is closest to the electrical panel at the moment
Re-energizing after a fault should be done only by trained, authorized persons who have determined the cause and confirmed it is safe, consistent with the safe work practices of Subpart K. Blindly resetting a breaker can re-create a fault, arc flash, or fire. The underlying problem must be corrected first.
Arc-rated (AR) clothing and a face shield or hood are selected based on:
- a.The brand of tools being used rather than the electrical hazard
- b.The incident energy or arc-flash category of the task✓
- c.The worker's personal color preference for the job-site uniform
- d.Only the outdoor temperature on the day the work is performed
Arc-rated PPE is selected so its arc thermal performance value meets or exceeds the incident energy of the potential arc flash, based on an arc-flash risk assessment following NFPA 70E and supported by 29 CFR 1926.416. Ordinary flammable clothing can ignite and worsen burns. PPE supplements, but does not replace, de-energizing.
Static electricity control (bonding and grounding) is important when:
- a.Reading a printed safety data sheet in a well-ventilated break area
- b.Transferring flammable liquids that a spark could ignite✓
- c.Sweeping the floor of an office trailer at the end of the shift
- d.Charging a cell phone battery from a standard wall receptacle indoors
Bonding and grounding containers during flammable-liquid transfer equalizes potential and drains static charge so a spark does not ignite vapors, a practice reflected in 29 CFR 1926.152 and general electrical safety. Static buildup during pouring or flow is a real ignition source. This complements Subpart K grounding principles.
What is the correct action for a damaged or defective portable electric tool?
- a.Lend it to a different crew so they can decide whether it is usable
- b.Cover the damaged area with electrical tape and keep using it as normal
- c.Continue using it carefully until a replacement can eventually be ordered
- d.Tag it out of service and remove it until repaired✓
A defective tool must be removed from service and tagged so no one uses it until it is repaired or replaced, consistent with 29 CFR 1926.416 and 1926.404(f). Continuing to use damaged equipment risks shock, arc flash, and fire. Repairs must restore it to a safe condition.
Ground-fault protection is most critical in which construction setting?
- a.Only on circuits that carry more than 1,000 volts to fixed machinery
- b.Only when no portable tools are being used anywhere on the site
- c.Only inside fully finished, climate-controlled office spaces
- d.Wet or damp locations and outdoor temporary power✓
Wet and damp locations sharply increase shock severity, so GFCI protection required by 29 CFR 1926.404(b)(1) is especially critical for outdoor temporary power and portable tools. Water lowers body resistance and makes ground faults more likely to injure. Connections should also be kept up off wet ground.
How often should cords, plugs, and portable tools be visually inspected on a construction site?
- a.Never, because visual inspection cannot reveal any real defects
- b.Before each use or shift✓
- c.Only once per calendar year during a scheduled formal audit
- d.Only after the equipment has already caused an injury to a worker
Cords, plugs, and tools should be visually inspected before each use or shift for damaged insulation, missing ground prongs, and defective plugs, supporting the requirements of 29 CFR 1926.416(e) and the assured grounding program. Early detection removes hazards before they cause injury. Defective items are tagged out.
Which best describes a 'qualified person' for electrical work under 29 CFR 1926?
- a.Anyone the crew leader designates verbally at the start of the shift
- b.One knowledgeable in the equipment and trained to avoid its hazards✓
- c.Any employee who has worked on the construction site for over one year
- d.A person who owns the necessary tools but has had no formal training
29 CFR 1926.449 defines a qualified person as one who, by knowledge and training, is familiar with the construction and operation of the equipment and the hazards involved. Qualification is task- and equipment-specific. Only qualified persons may perform certain energized electrical work.
Temporary lighting circuits and receptacles on a site should be protected so that:
- a.Bulbs hang bare and receptacles are wired straight to the service
- b.Only the office trailer has any overcurrent protection at all
- c.All wiring is buried in the concrete slab as it is being poured
- d.Bulbs are guarded and receptacles have GFCI protection✓
Temporary lighting must have guarded lamps (29 CFR 1926.405(a)(2)(ii)(E)) and temporary receptacles must have GFCI protection (1926.404(b)(1)). Together these controls address contact, breakage, and ground-fault shock hazards common with temporary power. Wiring must also be supported and protected from damage.
The main purpose of grounding the electrical system (as opposed to bonding) is to:
- a.Insulate all metal parts so no current can ever flow between them
- b.Provide the operating current that normally powers the connected tools
- c.Establish a reference to earth and stabilize voltage during faults✓
- d.Increase the resistance of the circuit to slow down electricity
System grounding connects the electrical system to earth to stabilize voltage and provide a reference and fault-current path, while bonding ties metal parts together to eliminate potential differences. Both are required by 29 CFR 1926.404(f) and work together for shock protection. Neither is the normal current-carrying path for loads.
Working in an elevated area near energized overhead lines, the safest control is to:
- a.Assume the lines are dead because no equipment is currently running
- b.Have the utility de-energize or insulate the lines before work✓
- c.Rely on the workers to simply watch the lines while they work quickly
- d.Move the lines by hand to a safer position before beginning the task
The most reliable control near overhead lines is to have the utility de-energize, relocate, or insulate them, then verify, before work begins; this appears in 29 CFR 1926.1408 and 1926.416. Where that is not possible, maintain the required clearances and use spotters. Never rely on visual watching alone at close range.
A 'flexible cord as fixed wiring' installation on a construction site is:
- a.Prohibited, because cords may not substitute for permanent wiring✓
- b.Allowed indefinitely as long as the cord is taped neatly to the wall
- c.Required by OSHA for all circuits that serve portable hand tools
- d.Encouraged, because flexible cords are cheaper than permanent wiring
29 CFR 1926.405(a)(2)(ii)(I) and (g) prohibit using flexible cords as a substitute for the fixed wiring of a structure or running them through walls, ceilings, or floors. Cords are for temporary and portable applications only. Permanent circuits require approved fixed wiring methods.
Why must the area around a temporary panel or transformer be kept clear of stored materials?
- a.So the equipment can be photographed easily for progress reports
- b.To make room for workers to eat lunch near the warm equipment
- c.To allow quick emergency access and safe working clearance✓
- d.Because stored materials would improve the panel's cooling airflow
Clear working space in front of electrical equipment, required by 29 CFR 1926.403(i), allows safe operation and rapid emergency shutoff. Storing materials in this space delays de-energizing and increases arc-flash exposure. The space must remain unobstructed at all times.
When servicing equipment with multiple energy sources (electrical, hydraulic, pneumatic), lockout must:
- a.Rely on a single tag placed on the most convenient valve or switch
- b.Address only the electrical source because it is the most obvious one
- c.Be skipped entirely if the machine has more than one energy source
- d.Isolate and control every hazardous energy source, not just electrical✓
Effective hazardous-energy control requires identifying and isolating all energy sources, electrical, hydraulic, pneumatic, mechanical, thermal, and stored, before servicing, consistent with 29 CFR 1926.417 and general lockout principles. Overlooking a secondary source can cause unexpected release or motion. Each source is locked, tagged, and verified at zero energy.
The 'restricted approach boundary' differs from the limited approach boundary in that it:
- a.May be crossed only by qualified persons using proper PPE and controls✓
- b.Marks the edge of the parking lot rather than an electrical hazard zone
- c.Applies only to de-energized equipment that has already been verified safe
- d.May be crossed by anyone at all as long as they move quickly through it
The restricted approach boundary, defined in NFPA 70E and supported by OSHA safe-work practices, is closer to exposed energized parts than the limited approach boundary and may be crossed only by qualified persons with appropriate PPE and documented controls. Crossing it raises the risk of shock and requires a plan. Unqualified persons may never cross it.
If a worker discovers a receptacle with reversed polarity or an open ground during testing, they should:
- a.Simply plug in a two-prong adapter and continue working normally
- b.Keep using it because polarity and grounding faults are harmless
- c.Report it only at the next scheduled monthly safety meeting
- d.Take it out of service and have it corrected before use✓
A receptacle with reversed polarity or an open ground has a wiring fault that defeats shock protection and must be taken out of service and corrected, supporting the grounding integrity required by 29 CFR 1926.404(f). Continued use exposes workers to shock if a tool faults. A qualified person makes the repair.
The primary reason to keep electrical connections and junction boxes covered on a site is to:
- a.Prevent contact with live parts and keep out moisture and debris✓
- b.Give the wiring a neater appearance for the client walkthrough
- c.Keep the connections warm so electricity flows through them faster
- d.Reduce the total length of cord needed to reach distant work areas
Covers on boxes and connections guard against inadvertent contact with energized parts and keep out water and debris that could cause faults, as required by 29 CFR 1926.405(b) and 1926.403(i). Open boxes expose live conductors and invite shock and short circuits. Covers and plates must be installed and kept intact.
Which is the best first action if a worker receives an electric shock but is no longer in contact with the source?
- a.Send them straight back to work since the shock has already ended
- b.Wait a full day before deciding whether any medical care is needed
- c.Give them a large drink of water and tell them to walk it off alone
- d.Call for emergency medical help and monitor them closely✓
Even after contact ends, an electric shock can cause delayed cardiac and internal injuries, so emergency medical help should be summoned and the worker monitored, consistent with the first-aid provisions of 29 CFR 1926.50. Do not assume the person is fine because they are conscious. Prompt evaluation can be lifesaving.
Ground-fault currents are dangerous mainly because they:
- a.Are always stopped instantly by any ordinary light switch
- b.Only heat the wiring and never present any hazard to people
- c.Can pass through a worker's body on the way to ground✓
- d.Improve the performance of tools by adding extra power to them
A ground fault occurs when current escapes the intended path and can flow through a worker's body to ground, causing shock or electrocution. GFCIs detect this leakage and interrupt power quickly, as required by 29 CFR 1926.404(b)(1). Grounding conductors provide the intended safe fault path.
Overhead and underground utility strikes during construction most often result from:
- a.Having too many spotters watching the equipment at one time
- b.Using tools that are too small to reach the utility lines at all
- c.Working only during clearly marked and well-lit daylight hours
- d.Failure to locate or maintain clearance from energized lines✓
Utility strikes typically result from failing to identify, locate, de-energize, or keep clearance from energized lines, addressed by 29 CFR 1926.416, 1926.1408, and the excavation rules of Subpart P. Planning, one-call locating, spotters, and clearance limits prevent them. All lines are treated as energized.
The purpose of an insulated (rubber) glove system with leather protectors is to:
- a.Provide extra grip so heavy tools are less likely to be dropped
- b.Identify which workers are supervisors by the color of the gloves
- c.Keep the worker's hands warm during cold-weather construction work
- d.Guard against shock while shielding the rubber from cuts and abrasion✓
Rated insulating rubber gloves protect against electric shock, and leather protectors shield the rubber from mechanical damage that would compromise its insulating value, following the PPE requirements of 29 CFR 1926.95 and 1926.416. The gloves must be voltage-rated and periodically tested. They protect only if kept in good condition.
Why must workers keep conductive items (jewelry, metal tapes, watchbands) away from energized parts?
- a.Jewelry violates the site dress code but poses no electrical risk
- b.Metal objects slow the worker down when moving between tasks
- c.Metal can bridge live parts and conduct current through the body✓
- d.Metal items simply distract other workers who see them shining
Conductive jewelry, metal rulers, and watchbands can bridge energized parts and provide a current path through the body, causing severe shock or burns. Safe electrical work practices under 29 CFR 1926.416 call for removing conductive articles near exposed energized parts. Nonconductive tools and materials are used instead.
When temporary power is distributed on a large site, spider boxes and portable outlet boxes should:
- a.Be left uncovered so workers can quickly see the internal wiring
- b.Be built on site from spare parts with no listing or certification
- c.Be listed for the use and provide GFCI protection on the outlets✓
- d.Be plugged directly into overhead power lines to save cable length
Portable outlet boxes ('spider boxes') for temporary power must be listed for the application and provide GFCI protection on their 120-volt receptacles, consistent with 29 CFR 1926.404(b)(1) and 1926.405. Homemade or damaged boxes create shock and fire hazards. They must be kept covered and off wet ground.
A key reason de-energizing is preferred over energized work is that it:
- a.Allows unqualified workers to perform all electrical tasks freely
- b.Removes the shock and arc-flash hazard at its source✓
- c.Eliminates the need for any training or qualification of workers
- d.Guarantees the job will always be finished faster than live work
De-energizing, verified by lockout/tagout under 29 CFR 1926.417, removes the electrical hazard entirely rather than merely protecting against it, making it the most effective control in the hierarchy. Energized work is a last resort with residual risk. Qualification and PPE are still required for any energized task that cannot be avoided.
What should be done with GFCI devices as part of routine use on the job site?
- a.Test them periodically using the built-in test button✓
- b.Disconnect them whenever they interrupt power to a running tool
- c.Assume they work forever without any testing after installation
- d.Replace them with standard receptacles once the project is underway
GFCIs should be tested periodically with the built-in test button to confirm they trip properly, supporting the ground-fault protection required by 29 CFR 1926.404(b)(1). A GFCI that fails to trip must be replaced. Testing verifies the life-saving function is intact.
Under OSHA's respirable crystalline silica standard for construction, what is the permissible exposure limit (PEL) as an 8-hour time-weighted average?
- a.There is no numeric limit as long as workers wear any dust mask
- b.500 micrograms per cubic meter, ten times the actual regulated limit
- c.50 micrograms per cubic meter of air✓
- d.5 milligrams per cubic meter measured only at the very end of the shift
29 CFR 1926.1153 sets the silica PEL at 50 micrograms per cubic meter (50 ug/m3) as an 8-hour TWA. Exposure above this level requires additional controls. Silica dust is released when cutting, grinding, or drilling concrete, brick, and stone.
What is the action level in OSHA's construction silica standard that triggers certain requirements such as exposure monitoring?
- a.25 micrograms per cubic meter as an 8-hour TWA✓
- b.The action level is the same as the permissible exposure limit exactly
- c.100 micrograms per cubic meter measured over any 15-minute period
- d.There is no action level defined anywhere in the silica standard
29 CFR 1926.1153 sets an action level of 25 ug/m3 as an 8-hour TWA, half the PEL, above which requirements such as exposure assessment and medical surveillance may apply. The action level provides a margin below the PEL. It helps ensure exposures are managed before they exceed the limit.
Table 1 of the construction silica standard allows an employer to:
- a.Substitute hearing protection for respiratory protection during cutting
- b.Follow specified control methods for a task instead of measuring exposure✓
- c.Skip all training as long as the task appears somewhere in the table
- d.Ignore silica dust entirely for any task listed in the table
Table 1 of 29 CFR 1926.1153 lists common construction tasks with specified engineering controls, work practices, and respiratory protection; employers who fully and properly implement the listed controls need not separately measure worker exposure. It simplifies compliance for common tasks. Controls such as water and vacuum dust collection are central to the table.
The construction silica standard requires each covered employer to have:
- a.Only a supply of disposable dust masks kept in the site office
- b.A written exposure control plan and a designated competent person✓
- c.A signed waiver from each worker accepting the risk of silicosis
- d.A single verbal warning given once at the start of the project
29 CFR 1926.1153 requires a written exposure control plan describing tasks, controls, and housekeeping, and designation of a competent person to implement it. The plan must be reviewed at least annually. The competent person makes frequent and regular inspections.
Under the silica standard, medical surveillance must be offered to employees who:
- a.Must wear a respirator under the standard for 30 or more days per year✓
- b.Request it for personal reasons unrelated to any silica exposure at work
- c.Have simply visited a construction site at any point during the year
- d.Work in any office role for the company regardless of dust exposure
29 CFR 1926.1153 requires the employer to make medical surveillance available to each employee who is required to use a respirator under the standard for 30 or more days per year. It includes a baseline exam, chest X-ray, and lung-function test. Early detection helps prevent progression of silica-related disease.
Which construction activity is a major source of respirable crystalline silica?
- a.Carrying finished lumber from a delivery truck to a storage rack
- b.Filling out injury and illness recordkeeping forms in the office
- c.Cutting, grinding, or drilling concrete, brick, or stone✓
- d.Reading printed blueprints in a climate-controlled site trailer
Silica dust becomes airborne when workers cut, grind, drill, crush, or abrade silica-containing materials such as concrete, brick, block, and stone, the activities regulated by 29 CFR 1926.1153. Controlling dust at the source with water or vacuum systems is the key protection. Dry cutting without controls produces the highest exposures.
A complete respiratory protection program under 29 CFR 1926.103 must include which core elements?
- a.A one-time signature confirming the worker owns a respirator
- b.Medical evaluation, fit testing, training, and maintenance✓
- c.Only handing out disposable masks whenever workers ask for them
- d.Nothing beyond posting a sign that reminds workers to breathe carefully
29 CFR 1926.103 incorporates 1910.134, which requires a written program with medical evaluation, fit testing for tight-fitting respirators, proper selection, training, maintenance, and program evaluation. Each element ensures the respirator actually protects the wearer. Respirators are used after engineering controls are applied.
Before a worker may be required to wear a tight-fitting respirator, they must first receive:
- a.A pay raise to compensate for the discomfort of wearing a mask
- b.A medical evaluation to ensure they can safely wear one✓
- c.A written test on the history of the respiratory protection standard
- d.Permission from every other member of the work crew on the site
Under 29 CFR 1910.134 (incorporated by 1926.103), a medical evaluation must be completed before fit testing or use, because respirator use can stress the heart and lungs. A physician or licensed health care professional reviews a questionnaire or exam. Workers found medically unable are not assigned tight-fitting respirators.
Why can facial hair along the sealing surface disqualify a worker from using a tight-fitting respirator?
- a.It makes the respirator too heavy for the worker to hold in place
- b.It prevents a proper face-to-facepiece seal, allowing contaminants to leak in✓
- c.It changes the color of the respirator and voids the manufacturer warranty
- d.It has no effect on the seal and is only a matter of company appearance rules
Facial hair that crosses the sealing surface of a tight-fitting respirator breaks the seal, letting contaminated air leak past the filter, so 29 CFR 1910.134 prohibits it for such respirators. A fit test cannot pass with an interfering beard. Loose-fitting powered respirators may be an alternative.
What are the two recognized methods for fit testing a tight-fitting respirator?
- a.Qualitative and quantitative fit testing✓
- b.Annual and monthly fit testing distinguished only by how often they occur
- c.Indoor and outdoor fit testing based only on where the worker stands
- d.Visual and verbal fit testing performed entirely without any equipment
29 CFR 1910.134 recognizes qualitative fit testing (relying on the wearer's taste, smell, or irritant response) and quantitative fit testing (using an instrument to measure leakage). Either method must be passed before use and repeated at least annually. The method chosen depends on the respirator and protection factor needed.
A filtering facepiece (N95) half-mask respirator has an assigned protection factor (APF) of:
- a.10✓
- b.1, meaning it provides no measurable reduction in exposure at all
- c.500, regardless of how the respirator is fitted to the wearer
- d.1,000, the same as a full self-contained breathing apparatus
OSHA's assigned protection factor table in 29 CFR 1910.134 gives filtering facepiece and other half-mask respirators an APF of 10, meaning they reduce exposure to about one-tenth if properly fitted. Higher-hazard exposures require respirators with higher APFs. The APF assumes a passing fit test and correct use.
In an atmosphere that is oxygen-deficient or immediately dangerous to life or health (IDLH), which respirator is required?
- a.A cloth face covering worn tightly against the nose and mouth
- b.No respirator, since low oxygen is not considered a real hazard
- c.An ordinary dust mask, which filters out low-oxygen conditions
- d.A supplied-air respirator or self-contained breathing apparatus (SCBA)✓
Air-purifying respirators only filter contaminants and cannot add oxygen, so oxygen-deficient or IDLH atmospheres require an atmosphere-supplying respirator such as a supplied-air respirator or SCBA, per 29 CFR 1910.134. Using a filter respirator in low oxygen can be fatal. Confined-space entries often require these devices.
When workers voluntarily use their own dust masks where exposures are below limits, the employer must still:
- a.Ignore the practice completely since voluntary use is unregulated
- b.Charge the worker a fee for each disposable mask they choose to wear
- c.Provide the information in Appendix D of the respirator standard✓
- d.Require a full medical exam and annual fit test for a paper dust mask
For voluntary use, 29 CFR 1910.134 requires the employer to provide users with the basic information in Appendix D, and for non-filtering-facepiece respirators, elements of the program still apply. This ensures voluntary use does not itself create a hazard. It balances worker choice with basic safeguards.
What is the permissible exposure limit for asbestos as an 8-hour time-weighted average?
- a.50 fibers per cubic centimeter measured only during active cutting
- b.There is no exposure limit for asbestos in construction work
- c.0.1 fiber per cubic centimeter of air✓
- d.1.0 fiber per cubic centimeter averaged over an entire 8-hour shift
29 CFR 1926.1101 sets the asbestos PEL at 0.1 fiber per cubic centimeter (f/cc) as an 8-hour TWA. A separate excursion limit applies to short-term exposures. Asbestos causes asbestosis, lung cancer, and mesothelioma.
In addition to the 8-hour PEL, the asbestos standard sets an excursion limit of:
- a.10 fibers per cubic centimeter averaged over any 12-hour period
- b.1.0 fiber per cubic centimeter averaged over 30 minutes✓
- c.There is no short-term limit, only the 8-hour average matters
- d.0.1 fiber per cubic centimeter averaged over a full 8-hour shift
29 CFR 1926.1101 sets an excursion limit of 1.0 f/cc averaged over 30 minutes, in addition to the 0.1 f/cc 8-hour PEL. The excursion limit controls brief high exposures. Regulated areas, wet methods, and negative-pressure enclosures help keep exposures below both limits.
Which diseases are most strongly associated with asbestos exposure?
- a.Temporary sneezing and mild watery eyes that clear within a day
- b.Improved lung capacity and increased resistance to respiratory infection
- c.Asbestosis, lung cancer, and mesothelioma✓
- d.Only minor skin irritation that resolves after washing with soap
Inhaled asbestos fibers can cause asbestosis (lung scarring), lung cancer, and mesothelioma, a cancer of the lining of the lungs or abdomen, as recognized in 29 CFR 1926.1101. These diseases often appear decades after exposure. There is no safe level of casual exposure, so controls are strict.
Which work practice is required (or prohibited) when disturbing asbestos-containing materials?
- a.Use wet methods and never dry-sweep or use compressed air on debris✓
- b.Dry-sweep the debris quickly to remove it before fibers settle
- c.Use compressed air to blow the dust away from the work area
- d.Allow the debris to dry out fully before disposing of it in the open
29 CFR 1926.1101 requires wet methods, HEPA vacuuming, and prompt cleanup, and prohibits dry sweeping and using compressed air, which would send fibers airborne. Debris is kept wet and sealed in labeled containers. Regulated areas limit access during the work.
What is the permissible exposure limit for lead in construction as an 8-hour TWA?
- a.30 micrograms per cubic meter, which is actually the action level
- b.50 micrograms per cubic meter of air✓
- c.There is no exposure limit for lead on construction projects
- d.500 micrograms per cubic meter averaged over a two-hour period
29 CFR 1926.62 sets the lead PEL at 50 ug/m3 as an 8-hour TWA. A separate action level triggers monitoring and other requirements. Lead exposure occurs during abrasive blasting, sanding, cutting, and welding of lead-painted surfaces.
The construction lead standard sets an action level of:
- a.200 micrograms per cubic meter measured only during welding
- b.50 micrograms per cubic meter, which is identical to the PEL
- c.There is no action level, only the permissible exposure limit
- d.30 micrograms per cubic meter as an 8-hour TWA✓
29 CFR 1926.62 sets the lead action level at 30 ug/m3 as an 8-hour TWA, which triggers exposure monitoring, training, and medical surveillance requirements. It is below the 50 ug/m3 PEL. Meeting the action level ensures protections begin before the PEL is exceeded.
Which activity is a common source of lead exposure in construction?
- a.Storing new, sealed cans of paint in a ventilated supply room
- b.Measuring a wall with a tape measure before any painting begins
- c.Sanding, cutting, or torch-burning surfaces coated with lead-based paint✓
- d.Reading the safety data sheet for a water-based latex paint indoors
Disturbing lead-based paint by sanding, grinding, cutting, abrasive blasting, or torch burning generates lead dust and fumes, the exposures regulated by 29 CFR 1926.62. Older structures commonly contain lead paint. Controls include containment, ventilation, wet methods, and respiratory protection.