OSHA construction welding and cutting study guide
Subpart J of OSHA's construction rules (29 CFR 1926.350 to 1926.354) covers welding and cutting in construction work. This guide sets out what the rule text states on handling and storing gas cylinders, fuel gas, manifolds, hose and torches, arc welding equipment and grounding, fire prevention, ventilation and confined spaces, toxic metals and inert-gas metal-arc welding, and preservative coatings. Consensus standards and other regulations the rule names (such as ANSI Z49.1-1967 and Compressed Gas Association Pamphlet P-1-1965) are only named here, not summarized. Every point links to the regulation and quotes its exact words.
Cylinder handling and storage
When cylinders are hoisted, they must be secured on a cradle, slingboard or pallet. Magnets and choker slings must not be used to hoist or transport them.
“When cylinders are hoisted, they shall be secured on a cradle, slingboard, or pallet. They shall not be hoisted or transported by means of magnets or choker slings.”
Cylinders must be moved by tilting and rolling them on their bottom edges, and must not be intentionally dropped, struck or permitted to strike each other violently.
“Cylinders shall be moved by tilting and rolling them on their bottom edges. They shall not be intentionally dropped, struck, or permitted to strike each other violently.”
Valve protection caps must not be used to lift cylinders from one vertical position to another, bars must not be used under valves or valve protection caps to pry frozen cylinders loose, and warm, not boiling, water must be used to thaw cylinders loose.
“Valve protection caps shall not be used for lifting cylinders from one vertical position to another. Bars shall not be used under valves or valve protection caps to pry cylinders loose when frozen. Warm, not boiling, water shall be used to thaw cylinders loose.”
Unless cylinders are firmly secured on a special carrier intended for this purpose, regulators must be removed and valve protection caps put in place before the cylinders are moved.
“Unless cylinders are firmly secured on a special carrier intended for this purpose, regulators shall be removed and valve protection caps put in place before cylinders are moved.”
Compressed gas cylinders must be secured upright at all times, except, if necessary, for short periods while they are actually being hoisted or carried.
“Compressed gas cylinders shall be secured in an upright position at all times except, if necessary, for short periods of time while cylinders are actually being hoisted or carried.”
Oxygen cylinders in storage must be separated from fuel-gas cylinders or combustible materials (especially oil or grease) by one of two options: a minimum of 20 feet, or a noncombustible barrier at least 5 feet high with a fire-resistance rating of at least one-half hour.
“Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet (6.1 m) or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.”
Inside buildings, cylinders must be stored in a well-protected, well-ventilated, dry location at least 20 feet from highly combustible materials such as oil or excelsior.
“Inside of buildings, cylinders shall be stored in a well-protected, well-ventilated, dry location, at least 20 feet (6.1 m) from highly combustible materials such as oil or excelsior.”
Cylinders must be kept far enough from the welding or cutting that sparks, hot slag or flame will not reach them; when that is impractical, fire resistant shields must be provided.
“Cylinders shall be kept far enough away from the actual welding or cutting operation so that sparks, hot slag, or flame will not reach them. When this is impractical, fire resistant shields shall be provided.”
Cylinders containing oxygen or acetylene or other fuel gas must not be taken into confined spaces.
“Cylinders containing oxygen or acetylene or other fuel gas shall not be taken into confined spaces.”
Not covered here
Compressed Gas Association Pamphlet P-1-1965 (1926.350(a)(12)) and the Department of Transportation cylinder specifications in 49 CFR part 178 (1926.350(c)(2)) are only named in the rule and are not summarized here. We only write what an official source states, so study these parts with your certifying program's materials.
Fuel gas, manifolds, hose and torches
1926.350(d) requires the employer to thoroughly instruct employees in the safe use of fuel gas, as the paragraph lists. First item: before a regulator is connected to a cylinder valve, the valve is to be opened slightly and closed immediately ("cracking", meant to clear the valve of dust or dirt that might otherwise enter the regulator), and the person cracking the valve is to stand to one side of the outlet, not in front of it.
“Use of fuel gas. The employer shall thoroughly instruct employees in the safe use of fuel gas, as follows: (1) Before a regulator to a cylinder valve is connected, the valve shall be opened slightly and closed immediately. (This action is generally termed “cracking” and is intended to clear the valve of dust or dirt that might otherwise enter the regulator.) The person cracking the valve shall stand to one side of the outlet, not in front of it.”
Another item in the fuel-gas instruction the employer must give under 1926.350(d): the cylinder valve is always to be opened slowly to prevent damage to the regulator, and, for quick closing, valves on fuel gas cylinders are not to be opened more than 1 1/2 turns.
“The cylinder valve shall always be opened slowly to prevent damage to the regulator. For quick closing, valves on fuel gas cylinders shall not be opened more than 1 1/2 turns.”
Also part of the employer's fuel-gas instruction under 1926.350(d): if a leak is found around the valve stem when the valve on a fuel gas cylinder is opened, the valve is to be closed and the gland nut tightened; if that does not stop the leak, use of the cylinder is to be discontinued and the cylinder properly tagged and removed from the work area.
“If, when the valve on a fuel gas cylinder is opened, there is found to be a leak around the valve stem, the valve shall be closed and the gland nut tightened. If this action does not stop the leak, the use of the cylinder shall be discontinued, and it shall be properly tagged and removed from the work area.”
Fuel gas and oxygen manifolds must bear the name of the substance they contain in letters at least 1-inch high, painted on the manifold or on a sign permanently attached to it.
“Fuel gas and oxygen manifolds shall bear the name of the substance they contain in letters at least 1-inch high which shall be either painted on the manifold or on a sign permanently attached to it.”
Fuel gas hose and oxygen hose must be easily distinguishable from each other (the contrast may be made by different colors or by surface characteristics that can be told apart by touch), must not be interchangeable, and a single hose with more than one gas passage must not be used.
“Fuel gas hose and oxygen hose shall be easily distinguishable from each other. The contrast may be made by different colors or by surface characteristics readily distinguishable by the sense of touch. Oxygen and fuel gas hoses shall not be interchangeable. A single hose having more than one gas passage shall not be used.”
When parallel sections of oxygen and fuel gas hose are taped together, not more than 4 inches out of 12 inches may be covered by tape.
“When parallel sections of oxygen and fuel gas hose are taped together, not more than 4 inches out of 12 inches shall be covered by tape.”
All hose in use carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or substance that may ignite, enter into combustion or be harmful to employees must be inspected at the beginning of each working shift, and defective hose removed from service.
“All hose in use, carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or substance which may ignite or enter into combustion, or be in any way harmful to employees, shall be inspected at the beginning of each working shift. Defective hose shall be removed from service.”
Hose that has been subject to flashback, or shows evidence of severe wear or damage, must be tested to twice its normal pressure, but in no case less than 300 p.s.i.
“Hose which has been subject to flashback, or which shows evidence of severe wear or damage, shall be tested to twice the normal pressure to which it is subject, but in no case less than 300 p.s.i.”
Torches must be lighted by friction lighters or other approved devices, not by matches or from hot work.
“Torches shall be lighted by friction lighters or other approved devices, and not by matches or from hot work.”
Oxygen cylinders and fittings must be kept away from oil or grease, and oxygen must not be directed at oily surfaces, greasy clothes, or within a fuel oil or other storage tank or vessel.
“Oxygen cylinders and fittings shall be kept away from oil or grease. Cylinders, cylinder caps and valves, couplings, regulators, hose, and apparatus shall be kept free from oil or greasy substances and shall not be handled with oily hands or gloves. Oxygen shall not be directed at oily surfaces, greasy clothes, or within a fuel oil or other storage tank or vessel.”
Not covered here
For details not covered in Subpart J, 1926.350(j) applies the technical portions of ANSI Z49.1-1967; that standard is only named here, not summarized. We only write what an official source states, so study these parts with your certifying program's materials.
Arc welding and cutting
Only manual electrode holders specifically designed for arc welding and cutting, with a capacity able to safely handle the maximum rated current required by the electrodes, may be used.
“Only manual electrode holders which are specifically designed for arc welding and cutting, and are of a capacity capable of safely handling the maximum rated current required by the electrodes, shall be used.”
Cable must be free from repair or splices for at least 10 feet from the end where the electrode holder is connected, except that cables with standard insulated connectors or with splices whose insulating quality equals that of the cable are permitted.
“Only cable free from repair or splices for a minimum distance of 10 feet from the cable end to which the electrode holder is connected shall be used, except that cables with standard insulated connectors or with splices whose insulating quality is equal to that of the cable are permitted.”
When a single ground return cable services more than one unit, its safe current-carrying capacity must equal or exceed the total specified maximum output capacities of all the units it services.
“When a single ground return cable services more than one unit, its safe current-carrying capacity shall equal or exceed the total specified maximum output capacities of all the units which it services.”
Pipelines containing gases or flammable liquids, and conduits containing electrical circuits, must not be used as a ground return.
“Pipelines containing gases or flammable liquids, or conduits containing electrical circuits, shall not be used as a ground return.”
The frames of all arc welding and cutting machines must be grounded, either through a third wire in the cable containing the circuit conductor or through a separate wire grounded at the source of the current.
“The frames of all arc welding and cutting machines shall be grounded either through a third wire in the cable containing the circuit conductor or through a separate wire which is grounded at the source of the current.”
1926.351(d) requires employers to instruct employees in the safe means of arc welding and cutting, as the paragraph lists. First item: when electrode holders are to be left unattended, the electrodes are to be removed and the holders placed or protected so that they cannot make electrical contact with employees or conducting objects.
“Operating instructions. Employers shall instruct employees in the safe means of arc welding and cutting as follows: (1) When electrode holders are to be left unattended, the electrodes shall be removed and the holders shall be so placed or protected that they cannot make electrical contact with employees or conducting objects.”
Also part of the employer's arc welding instruction under 1926.351(d): when the arc welder or cutter leaves the work or stops work for any appreciable length of time, or when the arc welding or cutting machine is to be moved, the power supply switch to the equipment is to be opened.
“When the arc welder or cutter has occasion to leave his work or to stop work for any appreciable length of time, or when the arc welding or cutting machine is to be moved, the power supply switch to the equipment shall be opened.”
Whenever practicable, arc welding and cutting operations must be shielded by noncombustible or flameproof screens that protect nearby employees and other persons from the direct rays of the arc.
“Whenever practicable, all arc welding and cutting operations shall be shielded by noncombustible or flameproof screens which will protect employees and other persons working in the vicinity from the direct rays of the arc.”
Not covered here
The additional requirements of 1926.406(c), which 1926.351(d)(5) refers to, are in Subpart K and are not covered here. We only write what an official source states, so study these parts with your certifying program's materials.
Fire prevention
When practical, objects to be welded, cut or heated must be moved to a designated safe location; if they cannot readily be moved, all movable fire hazards nearby must be taken to a safe place or otherwise protected.
“When practical, objects to be welded, cut, or heated shall be moved to a designated safe location or, if the objects to be welded, cut, or heated cannot be readily moved, all movable fire hazards in the vicinity shall be taken to a safe place, or otherwise protected.”
If the object cannot be moved and not all fire hazards can be removed, positive means must be taken to confine the heat, sparks and slag and to protect the immovable fire hazards from them.
“If the object to be welded, cut, or heated cannot be moved and if all the fire hazards cannot be removed, positive means shall be taken to confine the heat, sparks, and slag, and to protect the immovable fire hazards from them.”
No welding, cutting or heating may be done where flammable paints, other flammable compounds or heavy dust concentrations create a hazard.
“No welding, cutting, or heating shall be done where the application of flammable paints, or the presence of other flammable compounds, or heavy dust concentrations creates a hazard.”
Suitable fire extinguishing equipment must be immediately available in the work area and kept ready for instant use.
“Suitable fire extinguishing equipment shall be immediately available in the work area and shall be maintained in a state of readiness for instant use.”
When normal fire prevention precautions are not sufficient, additional personnel must be assigned to guard against fire during the work and for a sufficient period afterward to ensure no possibility of fire exists, and they must be instructed on the anticipated fire hazards and the firefighting equipment.
“When the welding, cutting, or heating operation is such that normal fire prevention precautions are not sufficient, additional personnel shall be assigned to guard against fire while the actual welding, cutting, or heating operation is being performed, and for a sufficient period of time after completion of the work to ensure that no possibility of fire exists. Such personnel shall be instructed as to the specific anticipated fire hazards and how the firefighting equipment provided is to be used.”
When welding, cutting or heating is done on walls, floors and ceilings, the same precautions must be taken on the opposite side as on the side where the welding is done.
“When welding, cutting, or heating is performed on walls, floors, and ceilings, since direct penetration of sparks or heat transfer may introduce a fire hazard to an adjacent area, the same precautions shall be taken on the opposite side as are taken on the side on which the welding is being performed.”
To prevent fire in enclosed spaces from gas escaping through leaking or improperly closed torch valves, the gas supply to the torch must be positively shut off at some point outside the enclosed space whenever the torch is not to be used or is left unattended for a substantial period, such as the lunch period. Overnight and at the change of shifts, the torch and hose must be removed from the confined space.
“For the elimination of possible fire in enclosed spaces as a result of gas escaping through leaking or improperly closed torch valves, the gas supply to the torch shall be positively shut off at some point outside the enclosed space whenever the torch is not to be used or whenever the torch is left unattended for a substantial period of time, such as during the lunch period. Overnight and at the change of shifts, the torch and hose shall be removed from the confined space.”
Before heat is applied to a drum, container or hollow structure, a vent or opening must be provided to release any built-up pressure.
“Before heat is applied to a drum, container, or hollow structure, a vent or opening shall be provided for the release of any built-up pressure during the application of heat.”
Not covered here
For welding, cutting and heating on steel pipelines containing natural gas, 1926.352(i) applies Department of Transportation rules in 49 CFR part 192, which are not covered here. We only write what an official source states, so study these parts with your certifying program's materials.
Ventilation and confined spaces
Local exhaust ventilation consists of freely movable hoods intended to be placed by the welder or burner as close as practicable to the work, and it must have enough capacity and be arranged to remove fumes and smoke at the source and keep their concentration in the breathing zone within the safe limits defined in Subpart D.
“Local exhaust ventilation shall consist of freely movable hoods intended to be placed by the welder or burner as close as practicable to the work. This system shall be of sufficient capacity and so arranged as to remove fumes and smoke at the source and keep the concentration of them in the breathing zone within safe limits as defined in subpart D of this part.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Oxygen must not be used for ventilation, comfort cooling, blowing dust from clothing, or cleaning the work area.
“Oxygen shall not be used for ventilation purposes, comfort cooling, blowing dust from clothing, or for cleaning the work area.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Except as provided in 1926.353(b)(2) and (c)(2), either general mechanical or local exhaust ventilation meeting the requirements of 1926.353(a) must be provided whenever welding, cutting or heating is done in a confined space.
“Except as provided in paragraph (b)(2) of this section, and paragraph (c)(2) of this section, either general mechanical or local exhaust ventilation meeting the requirements of paragraph (a) of this section shall be provided whenever welding, cutting, or heating is performed in a confined space.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
When sufficient ventilation cannot be obtained without blocking the means of access, employees in the confined space must be protected by air line respirators meeting Subpart E, and an employee on the outside must be assigned to maintain communication with those working inside and to aid them in an emergency.
“When sufficient ventilation cannot be obtained without blocking the means of access, employees in the confined space shall be protected by air line respirators in accordance with the requirements of subpart E of this part, and an employee on the outside of such a confined space shall be assigned to maintain communication with those working within it and to aid them in an emergency.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Where a welder must enter a confined space through a manhole or other small opening, a means must be provided to remove him quickly in an emergency; safety belts and lifelines used for this must be attached so his body cannot be jammed in a small exit opening, and an attendant with a pre-planned rescue procedure must be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.
“Where a welder must enter a confined space through a manhole or other small opening, means shall be provided for quickly removing him in case of emergency. When safety belts and lifelines are used for this purpose they shall be so attached to the welder's body that his body cannot be jammed in a small exit opening. An attendant with a pre-planned rescue procedure shall be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Welding, cutting and heating not involving the conditions or materials in 1926.353(b), (c) or (d) may normally be done without mechanical ventilation or respiratory protective equipment, but where unusual physical or atmospheric conditions cause an unsafe accumulation of contaminants, suitable mechanical ventilation or respiratory protective equipment must be provided.
“Welding, cutting, and heating, not involving conditions or materials described in paragraph (b), (c), or (d) of this section, may normally be done without mechanical ventilation or respiratory protective equipment, but where, because of unusual physical or atmospheric conditions, an unsafe accumulation of contaminants exists, suitable mechanical ventilation or respiratory protective equipment shall be provided.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Employees doing any type of welding, cutting or heating must be protected by suitable eye protective equipment meeting the requirements of Subpart E.
“Employees performing any type of welding, cutting, or heating shall be protected by suitable eye protective equipment in accordance with the requirements of subpart E of this part.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Not covered here
The safe limits in Subpart D and the respirator requirements in Subpart E, which this section points to, are not covered here. We only write what an official source states, so study these parts with your certifying program's materials.
Toxic metals and inert-gas metal-arc welding
In enclosed spaces, welding, cutting or heating involving zinc-bearing base or filler metals or zinc-coated metals, lead base metals, cadmium-bearing filler materials, or chromium-bearing or chromium-coated metals must be done with either general mechanical or local exhaust ventilation.
“Welding, cutting, or heating in any enclosed spaces involving the metals specified in this subparagraph shall be performed with either general mechanical or local exhaust ventilation meeting the requirements of paragraph (a) of this section: (i) Zinc-bearing base or filler metals or metals coated with zinc-bearing materials; (ii) Lead base metals; (iii) Cadmium-bearing filler materials; (iv) Chromium-bearing metals or metals coated with chromium-bearing materials.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
In enclosed spaces, work involving metals containing lead (other than as an impurity) or coated with lead-bearing materials, cadmium-bearing or cadmium-coated base metals, metals coated with mercury-bearing metals, or beryllium-containing base or filler metals must use local exhaust ventilation, or employees must be protected by air line respirators. Beryllium has a stricter rule (next point).
“Welding, cutting, or heating in any enclosed spaces involving the metals specified in this subparagraph shall be performed with local exhaust ventilation in accordance with the requirements of paragraph (a) of this section, or employees shall be protected by air line respirators in accordance with the requirements of subpart E of this part: (i) Metals containing lead, other than as an impurity, or metals coated with lead-bearing materials; (ii) Cadmium-bearing or cadmium-coated base metals; (iii) Metals coated with mercury-bearing metals; (iv) Beryllium-containing base or filler metals.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
For welding, cutting or heating in enclosed spaces on beryllium-containing base or filler metals, the rule adds that, because of its high toxicity, work involving beryllium must be done with both local exhaust ventilation and air line respirators.
“Beryllium-containing base or filler metals. Because of its high toxicity, work involving beryllium shall be done with both local exhaust ventilation and air line respirators.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
When welding, cutting or heating involving the metals listed in 1926.353(c)(1) and (c)(2) is done in the open air, employees must be protected by filter-type respirators meeting Subpart E, except that employees working on beryllium-containing base or filler metals must be protected by air line respirators meeting Subpart E.
“Employees performing such operations in the open air shall be protected by filter-type respirators in accordance with the requirements of subpart E of this part, except that employees performing such operations on beryllium-containing base or filler metals shall be protected by air line respirators in accordance with the requirements of subpart E of this part.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Other employees exposed to the same atmosphere as the welders or burners must be protected in the same manner as the welder or burner.
“Other employees exposed to the same atmosphere as the welders or burners shall be protected in the same manner as the welder or burner.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Employees must not be permitted to engage in, or be exposed to, inert-gas metal-arc welding until special precautions have been taken. Among them: the use of chlorinated solvents must be kept at least 200 feet from the exposed arc, unless shielded, and surfaces prepared with chlorinated solvents must be thoroughly dry before welding is permitted on them.
“Since the inert-gas metal-arc welding process involves the production of ultra-violet radiation of intensities of 5 to 30 times that produced during shielded metal-arc welding, the decomposition of chlorinated solvents by ultraviolet rays, and the liberation of toxic fumes and gases, employees shall not be permitted to engage in, or be exposed to the process until the following special precautions have been taken: (i) The use of chlorinated solvents shall be kept at least 200 feet, unless shielded, from the exposed arc, and surfaces prepared with chlorinated solvents shall be thoroughly dry before welding is permitted on such surfaces.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
When inert-gas metal-arc welding is done on stainless steel, the requirements of 1926.353(c)(2) must be met to protect against dangerous concentrations of nitrogen dioxide.
“When inert-gas metal-arc welding is being performed on stainless steel, the requirements of paragraph (c)(2) of this section shall be met to protect against dangerous concentrations of nitrogen dioxide.”
29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating
Preservative coatings
Before welding, cutting or heating begins on a surface covered by a preservative coating whose flammability is not known, a competent person must test it to determine its flammability.
“Before welding, cutting, or heating is commenced on any surface covered by a preservative coating whose flammability is not known, a test shall be made by a competent person to determine its flammability.”
29 CFR 1926.354, Welding, cutting, and heating in way of preservative coatings
Preservative coatings are considered highly flammable when scrapings burn with extreme rapidity.
“Preservative coatings shall be considered to be highly flammable when scrapings burn with extreme rapidity.”
29 CFR 1926.354, Welding, cutting, and heating in way of preservative coatings
When coatings are determined to be highly flammable, they must be stripped from the area to be heated to prevent ignition.
“When coatings are determined to be highly flammable, they shall be stripped from the area to be heated to prevent ignition.”
29 CFR 1926.354, Welding, cutting, and heating in way of preservative coatings
In enclosed spaces, all surfaces covered with toxic preservatives must be stripped of all toxic coatings for at least 4 inches from the area of heat application, or the employees must be protected by air line respirators meeting Subpart E.
“In enclosed spaces, all surfaces covered with toxic preservatives shall be stripped of all toxic coatings for a distance of at least 4 inches from the area of heat application, or the employees shall be protected by air line respirators, meeting the requirements of subpart E of this part.”
29 CFR 1926.354, Welding, cutting, and heating in way of preservative coatings
Coatings must be removed far enough from the heated area that the temperature of the unstripped metal will not be appreciably raised; artificial cooling of the surrounding metal may be used to limit the area that must be cleaned.
“The preservative coatings shall be removed a sufficient distance from the area to be heated to ensure that the temperature of the unstripped metal will not be appreciably raised. Artificial cooling of the metal surrounding the heating area may be used to limit the size of the area required to be cleaned.”
29 CFR 1926.354, Welding, cutting, and heating in way of preservative coatings
Sources
- eCFR: 29 CFR 1926.350, Gas welding and cutting (as of Nov 4, 2026)Checked November 6, 2026
- eCFR: 29 CFR 1926.351, Arc welding and cutting (as of Nov 4, 2026)Checked November 6, 2026
- eCFR: 29 CFR 1926.352, Fire prevention (as of Nov 4, 2026)Checked November 6, 2026
- eCFR: 29 CFR 1926.353, Ventilation and protection in welding, cutting, and heating (as of Nov 4, 2026)Checked November 6, 2026
- eCFR: 29 CFR 1926.354, Welding, cutting, and heating in way of preservative coatings (as of Nov 4, 2026)Checked November 6, 2026
Other OSHA Construction study guides: Introduction to OSHA, Fall protection, Scaffolds, Stairways and ladders, Electrical safety, Excavations, Personal protective equipment, Health hazards, Hazard communication, Respirable crystalline silica, General safety and health