OSHA 30 Construction — All Questions

Which safety data sheet section contains first-aid measures?

• a.Section 1, which lists the product name and supplier contact
• b.Section 16, which is reserved only for the revision date
• c.Section 4✓
• d.First-aid information is never included on a safety data sheet

Under the standardized 16-section SDS format required by 29 CFR 1910.1200, Section 4 covers first-aid measures. The consistent numbering lets workers find critical information quickly in an emergency. Section 8 covers exposure controls and PPE, and Section 2 covers hazard identification.

Which safety data sheet section describes exposure controls and personal protective equipment?

• a.Section 3, which lists the chemical composition and ingredients
• b.Section 14, which covers transport and shipping information only
• c.Section 8✓
• d.PPE information does not appear anywhere on a safety data sheet

In the 16-section SDS format under 29 CFR 1910.1200, Section 8 covers exposure controls and personal protection, including exposure limits, engineering controls, and recommended PPE. Workers consult it to select appropriate protection. Section 4 covers first aid and Section 7 covers handling and storage.

Safety data sheets must be made available to workers:

• a.Readily accessible in the work area during each work shift✓
• b.Only by written request mailed to the corporate headquarters
• c.Only to supervisors, who are not required to share them with workers
• d.Only once a year during the annual safety training session

29 CFR 1910.1200 (applied to construction by 1926.59) requires that SDSs be readily accessible to employees in their work area on every shift, whether in paper or reliable electronic form. Quick access is essential during a spill or exposure. Workers must be trained on how to use them.

When a hazardous chemical is transferred into a secondary (workplace) container, that container must:

• a.Be discarded at the end of every shift regardless of its contents
• b.Be left completely unlabeled since the worker knows what is inside
• c.Be marked only with the worker's initials and the current date
• d.Be labeled with the chemical's identity and hazard information✓

29 CFR 1910.1200 requires workplace (secondary) containers to be labeled with the product identifier and hazard information, unless the container is for the immediate use of the worker who filled it and stays in their control. Unlabeled containers cause dangerous mix-ups. Proper labeling maintains the chain of hazard information.

A permissible exposure limit (PEL) established by OSHA represents:

• a.The maximum legal airborne concentration a worker may be exposed to✓
• b.The minimum amount of a chemical that must be present to work safely
• c.A recommended target that carries no legal weight for employers
• d.The price limit an employer may spend on protective equipment

A PEL, set under standards such as 29 CFR 1926.55 and the substance-specific rules, is the maximum airborne concentration of a substance to which a worker may legally be exposed, usually as an 8-hour TWA. Exposures above the PEL require controls. PELs are enforceable limits, not mere suggestions.

Which of the following defines a confined space under OSHA's construction standard?

• a.Any outdoor area larger than a typical residential parking lot
• b.Any room in a building that does not have a working window
• c.Only underground spaces that are located below the water table
• d.Large enough to enter, with limited entry/egress, and not designed for continuous occupancy✓

29 CFR 1926.1202 defines a confined space as one that is large enough for a worker to enter and perform work, has limited or restricted means of entry or exit, and is not designed for continuous occupancy. Examples include tanks, vaults, manholes, and pits. Meeting all three criteria makes it a confined space.

A confined space becomes a 'permit-required' confined space when it:

• a.Is located more than fifty feet from the nearest site exit
• b.Has been entered by more than three workers earlier that same day
• c.Contains or could contain a serious hazard such as a hazardous atmosphere or engulfment✓
• d.Is simply painted a different color from the surrounding structure

Under 29 CFR 1926.1203, a confined space is permit-required if it has a hazardous atmosphere, engulfment potential, an internal configuration that could trap or asphyxiate, or any other recognized serious hazard. Such spaces require a permit, testing, and an attendant. These controls prevent asphyxiation and engulfment deaths.

An atmosphere is considered oxygen-deficient when the oxygen concentration falls below:

• a.There is no defined lower limit for breathable oxygen
• b.25 percent, which is actually well above the normal level
• c.19.5 percent✓
• d.10 percent, at which point workers only feel mildly tired

29 CFR 1926.1202 defines a hazardous atmosphere as including oxygen below 19.5 percent (deficient). Normal air is about 20.9 percent oxygen. Oxygen-deficient atmospheres can cause rapid loss of consciousness and death, so spaces must be tested before entry.

An oxygen-enriched atmosphere, considered hazardous, exists when oxygen exceeds:

• a.There is no upper limit because more oxygen is always safer
• b.23.5 percent✓
• c.50 percent, far above any level found in practice
• d.19.5 percent, which is actually the low end of the safe range

29 CFR 1926.1202 defines oxygen above 23.5 percent as an oxygen-enriched, hazardous atmosphere because it dramatically increases flammability and fire intensity. Materials that resist burning in normal air can ignite readily. Confined spaces are tested for both low and high oxygen before entry.

In what order should a confined space atmosphere be tested before entry?

• a.Flammable gases first, then toxic contaminants, then oxygen last
• b.Toxic contaminants first, then oxygen, then flammable gases last
• c.Oxygen first, then flammable gases, then toxic contaminants✓
• d.The order does not matter as long as all three are eventually tested

29 CFR 1926.1204 requires testing in the order of oxygen content first, then flammable gases and vapors, then toxic air contaminants. Oxygen is tested first because many combustible-gas meters need adequate oxygen to read correctly. This sequence gives accurate, reliable results before entry.

An entry permit for a permit-required confined space must include information such as:

• a.The space identity, hazards, acceptable entry conditions, and test results✓
• b.The paint color of the space and the brand of tools being used
• c.Nothing more than the entry supervisor's personal phone number
• d.Only the names of workers and the time they took their lunch break

29 CFR 1926.1206 requires the entry permit to document the space, purpose, date and duration, authorized entrants and attendants, hazards, control measures, acceptable entry conditions, and atmospheric test results. The permit is signed by the entry supervisor. It is posted or available to entrants during the entry.

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

• a.Staying outside, monitoring entrants, and ordering evacuation if needed✓
• b.Filling out payroll records while the entry is taking place
• c.Leaving the area once the entrants have safely climbed inside
• d.Entering the space to work alongside the authorized entrants

Under 29 CFR 1926.1209, the attendant remains outside the space, continuously monitors entrants and conditions, maintains communication, and orders evacuation and summons rescue if a hazard arises. The attendant must not enter to attempt rescue. This role is critical to preventing multiple-fatality incidents.

During confined-space rescue, why is entry rescue by untrained coworkers so dangerous?

• a.A large share of confined-space deaths are would-be rescuers✓
• b.Rescue is never needed because confined spaces are inherently safe
• c.The atmosphere improves automatically as soon as help arrives
• d.Rescuers always have more than enough time to act without any risk

Many confined-space fatalities are would-be rescuers who rush in and are overcome by the same hazard, which is why 29 CFR 1926.1211 requires planned rescue, non-entry retrieval systems where feasible, and trained rescuers. Untrained entry rescue creates additional victims. Retrieval lines and summoned rescue services are safer.

During entry into a permit space with a potential atmospheric hazard, monitoring should be:

• a.Performed only after a worker reports feeling dizzy or ill
• b.Done once before entry and then never repeated during the work
• c.Continuous or periodic as needed to detect changing conditions✓
• d.Skipped entirely if the space looked clean during a visual check

29 CFR 1926.1204 requires continuous or periodic monitoring as necessary to ensure the atmosphere stays within acceptable entry conditions throughout the entry. Conditions can change as work is performed. Entrants must evacuate if monitoring detects a hazard.

Carbon monoxide is especially dangerous in confined or poorly ventilated spaces because it is:

• a.Colorless and odorless, giving no warning of its presence✓
• b.Completely nontoxic and only a concern for its unpleasant smell
• c.Heavier than water and settles harmlessly at the bottom of tanks
• d.Bright red and gives off a strong odor that warns workers early

Carbon monoxide, produced by engines and combustion, is a colorless, odorless gas that provides no sensory warning and interferes with the blood's ability to carry oxygen. Gasoline-powered tools and generators must never run in enclosed spaces without ventilation, per hazard control under 29 CFR 1926.55 and Subpart AA. CO detectors and ventilation are essential.

Hydrogen sulfide (H2S) is particularly hazardous because at higher concentrations it:

• a.Turns bright green, making it easy to see and avoid at all times
• b.Deadens the sense of smell, so workers lose their warning of exposure✓
• c.Becomes completely harmless once the rotten-egg odor disappears
• d.Only causes mild eye watering and never affects breathing at all

Hydrogen sulfide has a rotten-egg odor at low levels, but at higher concentrations it rapidly deadens the sense of smell and can cause collapse and death, so odor is not a reliable warning. It is common in sewers, manholes, and oil-and-gas work. Atmospheric testing under Subpart AA is required rather than relying on smell.

Welding, cutting, and brazing can produce hazardous fumes, so OSHA requires:

• a.Workers to hold their breath during each welding operation
• b.Adequate ventilation or respiratory protection to control the fumes✓
• c.No controls at all because welding fumes are considered harmless
• d.That the work always be done inside a small, sealed room

29 CFR 1926.353 requires mechanical ventilation or respiratory protection to control fumes and gases from welding, cutting, and brazing, especially in confined spaces or with toxic metals. Some coatings (such as those containing lead, cadmium, or zinc) create especially dangerous fumes. Local exhaust ventilation is a key control.

Airborne concentrations of gases, vapors, fumes, dusts, and mists in construction are limited by:

• a.Only the outdoor weather conditions on the day of the work
• b.The permissible exposure limits referenced in 29 CFR 1926.55✓
• c.Nothing, since airborne contaminants are not regulated in construction
• d.The personal preference of each worker about air quality

29 CFR 1926.55 requires that employee exposure to airborne contaminants be kept within the permissible exposure limits (referencing the 1910.1000 tables) through feasible administrative or engineering controls, with respirators when needed. It covers gases, vapors, fumes, dusts, and mists. Ventilation and substitution are common controls.

Musculoskeletal disorders (MSDs) in construction are most associated with which risk factors?

• a.Wearing high-visibility clothing during outdoor daytime work
• b.Working only at a comfortable desk in a climate-controlled office
• c.Reading printed instructions and attending safety meetings
• d.Repetition, forceful exertions, and awkward or sustained postures✓

Ergonomic risk factors for MSDs include repetitive motions, high force, awkward and sustained postures, vibration, and manual lifting. OSHA addresses these primarily through the General Duty Clause and guidance, since there is no specific construction ergonomics standard. Controls include job rotation, mechanical aids, and better tool and task design.

Because there is no specific OSHA construction ergonomics standard, ergonomic hazards are addressed under:

• a.A detailed numeric lifting limit written directly into Part 1926
• b.The fall protection standard in Subpart M of Part 1926
• c.The General Duty Clause and OSHA/NIOSH guidance✓
• d.No authority at all, so employers have no ergonomic responsibilities

In the absence of a specific ergonomics rule, OSHA can cite recognized serious ergonomic hazards under the General Duty Clause, Section 5(a)(1) of the OSH Act, and relies on NIOSH guidance such as the lifting equation. Employers are still expected to reduce MSD risks. Engineering out the hazard is preferred over relying on technique alone.

Which is the most effective way to reduce back-injury risk from moving heavy materials?

• a.Use mechanical aids such as carts, hoists, and dollies✓
• b.Carry loads far from the body to keep them away from the legs
• c.Twist sharply at the waist while carrying loads to save steps
• d.Lift the heaviest loads alone and as quickly as possible each time

Substituting mechanical handling (carts, hoists, forklifts) removes the manual-lifting hazard, ranking above technique in the hierarchy of controls, and is preferred under OSHA/NIOSH ergonomic guidance. Where lifting is unavoidable, keep the load close, lift with the legs, and avoid twisting. Team lifting helps with heavy or awkward loads.

The bloodborne pathogens most of concern for occupational exposure are:

• a.Food-borne bacteria that cause temporary stomach upset
• b.Fungal infections that only affect the skin of the hands
• c.The common cold and seasonal influenza spread through the air
• d.Hepatitis B, hepatitis C, and HIV✓

29 CFR 1910.1030 (applicable to construction first-aid providers and similar exposures) focuses on bloodborne pathogens including hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV. These are transmitted through contact with infectious blood or body fluids. An exposure control plan and universal precautions reduce the risk.

'Universal precautions' or 'standard precautions' mean that a worker should:

• a.Treat all blood and certain body fluids as if they are infectious✓
• b.Assume blood is safe unless a coworker says otherwise
• c.Handle blood with bare hands as long as there are no visible cuts
• d.Test every source individual before providing any first aid

Under 29 CFR 1910.1030, universal (standard) precautions require treating all human blood and certain body fluids as if they are infectious, using PPE such as gloves and following safe practices regardless of the source's known status. This eliminates guesswork about who might be infected. It is the foundation of bloodborne pathogen protection.

When employees have occupational exposure to bloodborne pathogens, the hepatitis B vaccine must be:

• a.Provided only after the worker has already been infected once
• b.Mandatory, with no option for the worker to decline the shot
• c.Offered free of charge, generally within 10 working days of assignment✓
• d.Purchased by the employee out of their own paycheck each year

29 CFR 1910.1030 requires the employer to offer the hepatitis B vaccination series at no cost to employees with occupational exposure, generally within 10 working days of initial assignment. Workers may decline by signing a declination form and still request it later. The vaccine prevents a serious liver infection.

A workplace covered by the bloodborne pathogens standard must maintain:

• a.A plan that is written once and then never updated afterward
• b.A verbal understanding that workers should be careful with blood
• c.Only a first-aid kit with no written procedures of any kind
• d.A written exposure control plan reviewed at least annually✓

29 CFR 1910.1030 requires a written exposure control plan that identifies exposed job tasks, controls, and procedures, and it must be reviewed and updated at least annually and when tasks change. The plan drives training, PPE, and post-exposure follow-up. It must be accessible to employees.

Contaminated sharps, such as used needles, must be:

• a.Recapped by hand and dropped into an ordinary trash bag
• b.Left on the work surface until the end of the shift for counting
• c.Placed in a closable, puncture-resistant, labeled sharps container✓
• d.Carried loose in a pocket until a disposal area can be found

29 CFR 1910.1030 requires that contaminated sharps be discarded immediately in closable, puncture-resistant, leakproof, labeled or color-coded containers. Recapping by hand is prohibited to avoid needlestick injuries. Proper sharps disposal prevents exposure to bloodborne pathogens.

On a construction site without a nearby infirmary or clinic, OSHA requires:

• a.Only a telephone number for the nearest hospital posted on a wall
• b.A full-time physician stationed at every construction project
• c.A person trained in first aid and adequate first-aid supplies on site✓
• d.Nothing, because workers are expected to treat their own injuries

29 CFR 1926.50 requires that, when no infirmary, clinic, or hospital is reasonably accessible, a person trained in first aid be available and adequate first-aid supplies be provided. This ensures prompt care for injuries. Provisions for emergency transport must also be in place.

Heat stroke differs from heat exhaustion in that heat stroke:

• a.Requires no response other than telling the worker to drink water
• b.Is a mild condition that resolves quickly with a short rest break
• c.Is a life-threatening emergency with high body temperature and confusion✓
• d.Causes only heavy sweating and never affects mental awareness

Heat stroke is a medical emergency in which the body's temperature regulation fails, producing very high body temperature, confusion, slurred speech, and possibly loss of consciousness; skin may be hot and dry or wet. It requires calling 911 and rapid cooling. OSHA addresses heat illness under the General Duty Clause and its heat-illness prevention guidance.

If a worker shows signs of heat stroke (confusion, very hot skin, collapse), coworkers should:

• a.Wait to see whether the symptoms go away on their own after an hour
• b.Give the worker salt tablets and send them back to finish the task
• c.Call 911 immediately and begin rapidly cooling the worker✓
• d.Move the worker into direct sunlight to help them warm up further

Heat stroke requires calling emergency services at once and actively cooling the worker (shade, cool water, ice packs, fanning) while awaiting help, because delay can be fatal. This response reflects OSHA heat-illness prevention guidance under the General Duty Clause. Never leave a suspected heat-stroke victim alone.

Which is an early warning sign of hypothermia in cold-weather work?

• a.Uncontrolled shivering along with confusion or fumbling hands✓
• b.Rapid, clear thinking and a stronger grip than usual on tools
• c.Feeling comfortably warm despite the freezing air temperature
• d.A sudden burst of energy and improved fine motor coordination

Early hypothermia produces shivering, loss of coordination, fumbling, confusion, and slurred speech as the body's core temperature drops. As it worsens, shivering may stop, a dangerous sign. OSHA addresses cold stress under the General Duty Clause and provides prevention guidance.

Frostbite most commonly affects which parts of the body?

• a.Extremities such as fingers, toes, ears, nose, and cheeks✓
• b.Only the large muscles of the thighs during heavy exertion
• c.The lungs, causing an immediate loss of the ability to breathe
• d.The core organs of the chest and abdomen before anything else

Frostbite, the freezing of skin and underlying tissue, most often affects exposed and poorly circulated extremities: fingers, toes, ears, nose, and cheeks. Symptoms include numbness and waxy, discolored skin. Cold-stress prevention under OSHA guidance includes insulated PPE and warm-up breaks.

An effective way to prevent cold stress during winter construction is to:

• a.Drink alcohol to feel warmer while continuing to work outdoors
• b.Dress in layers, stay dry, and take breaks in warm areas✓
• c.Skip all breaks so the work is finished before it gets colder
• d.Wear a single heavy cotton layer that traps sweat against the skin

Cold-stress prevention includes wearing appropriate insulating layers, keeping clothing dry, staying hydrated, scheduling warm-up breaks, and monitoring workers, consistent with OSHA cold-stress guidance under the General Duty Clause. Alcohol actually increases heat loss and is unsafe. Wet clothing dramatically accelerates cooling.

Heat-illness risk is often measured using indicators such as:

• a.The distance from the job site to the nearest coffee shop
• b.The total number of tools in use on the job site that day
• c.The color of the workers' hard hats worn during the shift
• d.The heat index or wet bulb globe temperature (WBGT)✓

Employers assess heat-illness risk using measures such as the heat index (temperature plus humidity) and, more precisely, the wet bulb globe temperature (WBGT), which also accounts for radiant heat and wind. These guide work/rest schedules and acclimatization. OSHA promotes their use under its heat-illness prevention campaign.

New or returning workers are at especially high risk of heat illness because they:

• a.Have not yet acclimatized to working in the heat✓
• b.Automatically tolerate heat better than long-time workers do
• c.Are always the strongest and most experienced members of the crew
• d.Never need water, rest, or shade during their first week on the job

Workers who are new to heat or returning after time away have not yet acclimatized, and a large share of heat fatalities occur in the first few days on the job. Gradually increasing exposure over one to two weeks builds tolerance, per OSHA heat-illness guidance. New workers need closer monitoring and more frequent breaks.

OSHA sanitation rules for construction sites require employers to provide:

• a.Potable drinking water and adequate toilet facilities✓
• b.No water at all, since workers should bring their own supply
• c.Only a single shared cup for all workers to drink from
• d.Water that workers must purchase from a vending machine

29 CFR 1926.51 requires employers to provide an adequate supply of potable drinking water, along with sanitary facilities such as toilets, on construction sites. Common drinking cups are prohibited. Access to water supports hydration and helps prevent heat illness.

Repeated skin contact with solvents, cements, and wet concrete can cause:

• a.Occupational dermatitis, burns, or sensitization of the skin✓
• b.Permanent improvement in the skin's resistance to all chemicals
• c.Stronger fingernails and healthier skin over time with exposure
• d.Only a pleasant cooling sensation with no lasting health effect

Skin contact with solvents, epoxies, cements, and wet concrete (which is caustic) can cause irritant or allergic contact dermatitis, chemical burns, and sensitization, hazards addressed through PPE and hygiene under 29 CFR 1926.28 and 1926.95. Chemical-resistant gloves and prompt washing reduce the risk. Wet concrete's alkalinity can cause serious burns with prolonged contact.

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.