Machine guarding requirements

Under 1917.151(a), "guarded" means the hazard is physically shielded, fenced, enclosed, or made inaccessible by location or other methods so employees cannot contact moving parts. See the definition in 1917.151(a).

• Examples include covers, casings, shields, troughs, spillways, railings, guarding by location, and point-of-operation guarding such as barrier guards or two-hand tripping devices.
• Use the method that reasonably prevents access to the danger zone while allowing safe operation and maintenance (for more on point-of-operation options, see 1917.151(a)).

(Cited: 1917.151(a)).

Under 1917.151(b)(1), any danger zone on machines and equipment used by employees must be guarded. See 1917.151(b)(1).

• "Danger zones" include points of operation, rotating parts, nip points, shear points, and any area where employees could contact moving parts or be struck by flying debris.

(Cited: 1917.151(b)(1)).

Under 1917.151(b)(2), the employer must provide an effective exhaust system at the point of origin or an equally effective means to protect the operator from hazardous chips and dust. See 1917.151(b)(2).

• Local exhaust ventilation at the source is preferred; if not feasible, use other controls (enclosures, extraction hoods, or PPE when engineering controls are not sufficient).
• Regularly inspect and maintain the exhaust system so it remains effective.

(Cited: 1917.151(b)(2)).

Under 1917.151(b)(3), fixed machinery must be secured in place to prevent shifting during operation. See 1917.151(b)(3).

• Secure anchors, bolts, or appropriate mounts should be used so the machine cannot move, vibrate loose, or tip while running.
• Periodically verify that anchors and supports remain tight and undamaged.

(Cited: 1917.151(b)(3)).

Under 1917.151(b)(4), yes — a power cut-off device must be provided at the operator's working position. See 1917.151(b)(4).

• The device should let the operator quickly stop power to the machine without leaving the work area.
• Ensure the switch is clearly marked and kept free of obstructions so it can be used in an emergency.

(Cited: 1917.151(b)(4)).

Under 1917.151(b)(5), machines driven by belts and shafting must have a belt-locking or equivalent protective device if the belt can be shifted. See 1917.151(b)(5).

• This prevents a belt from slipping or jumping off during operation and exposing rotating parts.
• If the belt is fixed so it cannot shift, the requirement for a belt-locking device may not apply, but guarding must still prevent access to moving parts.

(Cited: 1917.151(b)(5)).

Under 1917.151(b)(6), employers must prevent machines from automatically restarting upon restoration of power when a restart could cause injury to the operator. See 1917.151(b)(6).

• Install a manual restart control or interlock that requires the operator to intentionally restart the machine.
• Verify that any automatic-restart prevention devices are maintained and tested periodically.

(Cited: 1917.151(b)(6)).

Under 1917.151(b)(7), the power supply to machines must be turned off, locked out, and tagged out during repair, adjustment, or servicing. See 1917.151(b)(7).

• Use an appropriate lockout/tagout procedure so no one can restore power while work is underway.
• Only trained, authorized employees should perform lockout/tagout and remove locks/tags after ensuring it's safe to re-energize.

(Cited: 1917.151(b)(7)).

Under 1917.151(b)(8), machines must be maintained in a safe working condition. See 1917.151(b)(8).

• Regular inspection, lubrication, alignment, and replacement of worn parts are common maintenance practices.
• Take machines out of service or tag them if defects that affect safety are found (see 1917.151(b)(10)).

(Cited: 1917.151(b)(8)).

Under 1917.151(b)(9), only designated employees are permitted to maintain or repair machinery and equipment. See 1917.151(b)(9).

• "Designated" means those employees the employer has identified and trained to perform maintenance or repairs safely.
• Designated employees should be familiar with lockout/tagout, safe procedures, and the hazards of the specific equipment.

(Cited: 1917.151(b)(9)).

Under 1917.151(b)(10), machines that have defects affecting safety must not be used. See 1917.151(b)(10).

• If you discover a defect that could endanger employees, remove the machine from service until the defect is corrected.
• Post clear warnings or lockout/tagout equipment to prevent use while the defect remains.

(Cited: 1917.151(b)(10)).

Under 1917.151(c)(1) and (c)(2), hand-fed circular ripsaws and hand-fed circular crosscut table saws must have hoods that completely enclose portions of the saw above the table and the material being cut, and they must have spreaders to prevent the material from squeezing the saw. See 1917.151(c)(1) and 1917.151(c)(2).

• Hoods should protect the operator from contact with the blade and from flying debris.
• Spreaders must be aligned with the saw to keep the cut material from closing on the blade.

(Cited: 1917.151(c)(1) and 1917.151(c)(2)).

Under 1917.151(c)(3), spreaders may be removed only during grooving, dadoing, or rabbeting operations and must be replaced when those operations are finished. See 1917.151(c)(3).

• Remove spreaders only for the specific cuts that require their absence, and replace them immediately after completing that work.
• This minimizes the time the operator is exposed to increased kickback or binding risk.

(Cited: 1917.151(c)(3)).

Under 1917.151(c)(3), yes — hand-fed circular saws shall have non-kickback fingers or dogs to oppose the saw's tendency to pick up or throw material toward the operator. See 1917.151(c)(3).

• Non-kickback devices help prevent the workpiece from being lifted or thrown by the blade.
• Keep these devices adjusted and in good condition so they function effectively.

(Cited: 1917.151(c)(3)).

Under 1917.151(d)(1), swing cutoff saws must have hoods that completely enclose the upper half of the saw, the arbor end, and the point of operation at all positions, and the hood must automatically cover the lower portion of the blade so it contacts the table or material as the saw moves. See 1917.151(d)(1).

• The hood must rise onto the fence when the saw returns and lower as the saw moves forward, maintaining contact with the table or stock.
• This arrangement protects the operator from thrown material and blade contact across the saw's travel.

(Cited: 1917.151(d)(1)).

Under 1917.151(d)(2), swing cutoff saws must have a device that returns the saw automatically to the back of the table without rebound, and that device must not rely on rope, cord, or springs. See 1917.151(d)(2).

• The return mechanism should provide smooth, controlled return and prevent the saw from snapping back toward the operator.
• Examples include hydraulic or geared returns designed for reliable, rebound-free motion.

(Cited: 1917.151(d)(2)).

Under 1917.151(d)(3) and (d)(4), swing cutoff saws must have devices to prevent swinging beyond the table's front or back edges, and inverted swing cutoff saws must have hoods covering the part of the saw protruding above the table top or the material. See 1917.151(d)(3) and 1917.151(d)(4).

• Use positive stops or mechanical limits to prevent overtravel of the saw.
• For inverted saws, ensure the hood adequately covers exposed blade portions above the table or stock.

(Cited: 1917.151(d)(3) and 1917.151(d)(4)).

Under 1917.151(e)(1), radial saws must have an upper hood that encloses the upper portion of the blade up to the arbor end and must have side guarding on the lower exposed portion adjusted automatically to the stock thickness and remaining in contact with the stock; the lower guard may be removed only for bevel cuts. See 1917.151(e)(1).

• The lower guard should follow the stock closely to minimize the exposed portion of the blade.
• Keep guards adjusted so they stay in contact with the material during cutting.

(Cited: 1917.151(e)(1)).

Under 1917.151(e)(2) and (e)(5), radial saws used for ripping must have non-kickback fingers or dogs on both sides to resist the saw's tendency to pick up or throw material, and employers must require employees to rip and plough against the saw's turning direction while the hood must conspicuously mark rotation direction and the end of the saw to use. See 1917.151(e)(2) and 1917.151(e)(5).

• Use non-kickback devices on both sides for ripping to minimize kickback risk.
• Mark the rotation direction and the end of the saw intended for use so operators can easily confirm proper setup.

(Cited: 1917.151(e)(2) and 1917.151(e)(5)).

Under 1917.151(e)(3) and (e)(4), radial saws must have an adjustable stop to prevent blade travel beyond the table's edge, and they must be installed so the cutting head returns to the starting position without rebound when released. See 1917.151(e)(3) and 1917.151(e)(4).

• The adjustable stop prevents overtravel that could expose the operator to hazards.
• The return mechanism should be smooth and controlled to avoid sudden movement toward the operator.

(Cited: 1917.151(e)(3) and 1917.151(e)(4)).

Under 1917.151(f), band saw blades and wheels must be enclosed or guarded except for the working portion between the bottom of the guide rolls and the table; band saws must have brakes to stop the wheel if the blade breaks and a tension control device to keep the blade taut. See 1917.151(f)(1), 1917.151(f)(2), and 1917.151(f)(3).

• Enclose wheels and non-working blade runs to protect employees from point-of-operation hazards and flying debris.
• Maintain brakes and tension devices to reduce the hazard of blade breakage or derailment.

(Cited: 1917.151(f)(1), 1917.151(f)(2), 1917.151(f)(3)).

Under 1917.151(g), abrasive wheels must be used only on machines having enclosure guards to restrain wheel fragments and protect employees (with limited exceptions), the safety guard opening must be adjustable when the operator stands in front of it, and fixed grinding machines must have rigid, adjustable work rests set within 1/8 inch of the wheel. See 1917.151(g)(1) and 1917.151(g)(4).

• Guards must be aligned with the wheel and fastened with hardware stronger than the guard itself.
• Adjust work rests to maintain a maximum opening of 1/8 inch and do not adjust them while the wheel is moving.
• Also follow requirements for wheel fit, spindle nut tightening, compatible wheel speed, proper flanges, and do not use abrasive wheels with operational defects (1917.151(g)(5)-(8)).

(Cited: 1917.151(g)(1) and 1917.151(g)(4)).

Under 1917.151(g)(3), guarding is not required for wheels used for internal work where the wheel is contained within the workpiece, and for mounted wheels 2 inches (5 cm) and smaller used in portable operations. See 1917.151(g)(3)(i) and 1917.151(g)(3)(ii).

• Even when a guard is not required by this paragraph, evaluate whether other controls or PPE are needed based on the specific operation.

(Cited: 1917.151(g)(3)(i) and 1917.151(g)(3)(ii)).

Under 1917.151(h)(1) and (h)(2), rotating parts such as gears and pulleys located 7 feet (2.13 m) or less above working surfaces must be guarded to prevent contact, and belt, rope, and chain drives must be guarded to prevent employee contact with moving parts. See 1917.151(h)(1) and 1917.151(h)(2).

• Install fixed barriers, covers, or guards that prevent reach or accidental contact.
• For elevated rotating parts above 7 ft, evaluate risk and guard where employee contact is reasonably possible.

(Cited: 1917.151(h)(1) and 1917.151(h)(2)).

Under Part 1917, the marine terminals standards generally do not apply to a "designated waterfront facility" used solely for bulk storage, handling, and transfer of liquids or gases; OSHA's letter explains those terminal-specific standards do not apply to such facilities. See the OSHA Letter of Interpretation on applicability to waterfront facilities at https://www.osha.gov/laws-regs/standardinterpretations/2017-05-31.

• The letter clarifies that because a designated waterfront facility falls within the definition of a "marine terminal," certain Part 1917 requirements (and some Part 1910 standards) are not applicable as written to that facility; confirm applicability for your specific operation with OSHA or the Office of Maritime Enforcement.

(Cited: OSHA Letter of Interpretation: https://www.osha.gov/laws-regs/standardinterpretations/2017-05-31 and general Part 1917 reference at 1917).

Yes — adding a strobe light that affects a vehicle's safety or operation may require the manufacturer's written approval or a written approval from a professional engineer, and operators may need refresher training. See the OSHA Letter of Interpretation about strobe lights on industrial trucks at https://www.osha.gov/laws-regs/standardinterpretations/2004-12-21-0.

• For marine terminal or longshoring equipment, the letter points to requirements that safety devices not be removed or made inoperative and that modifications affecting capacity or safety require approval.
• If approval cannot be obtained from the manufacturer, written approval from a qualified Registered Professional Engineer may be acceptable after safety analysis.

(Cited: OSHA Letter of Interpretation: https://www.osha.gov/laws-regs/standardinterpretations/2004-12-21-0 and general Part 1917 reference at 1917).

Under 1917.151(b)(9) and (b)(7), only designated employees may maintain or repair machinery, and the power supply must be turned off, locked out, and tagged out during repair, adjustment, or servicing. See 1917.151(b)(9) and 1917.151(b)(7).

• Guards should not be removed by unauthorized personnel for routine operation; removal is permitted only for necessary servicing by trained, designated employees following lockout/tagout procedures.
• After servicing, guards must be reinstalled and the machine returned to a safe condition before normal operation resumes.

(Cited: 1917.151(b)(9) and 1917.151(b)(7)).

Under 1917.151(g)(6), grinding machine wheels must turn at a speed compatible with the wheel's rated speed. See 1917.151(g)(6).

• Do not exceed the wheel's maximum rated RPM; operating above rated speed increases risk of wheel failure.
• Verify wheel specifications and machine RPM before mounting a wheel.

(Cited: 1917.151(g)(6)).

Under 1917.151(g)(7), flanges and blotters must be used only with wheels designed for their use, and flanges must be of a type that retains wheel fragments in case of breakage. See 1917.151(g)(7).

• Use manufacturer-recommended flanges and blotters sized to the wheel.
• Proper flanges reduce the likelihood of wheel disintegration and help hold wheel parts in place if the wheel fails.

(Cited: 1917.151(g)(7)).

Under 1917.151(g)(8), abrasive wheels with operational defects must not be used. See 1917.151(g)(8).

• Inspect wheels for cracks, chips, or other damage before mounting and during use; discard or replace defective wheels.
• Document inspections and ensure employees know how to recognize wheel defects.

(Cited: 1917.151(g)(8)).

Under 1917.151(b)(10) and (b)(8), the employer must stop using machines with safety-affecting defects and maintain machines in safe working condition, so if guarding is damaged or missing you must remove the machine from service or prevent use until guards are repaired and the machine is safe. See 1917.151(b)(10) and 1917.151(b)(8).

• Lockout/tagout the machine for repairs and allow only designated employees to perform the fix.
• Document the defect and corrective action to prevent recurrence.

(Cited: 1917.151(b)(10) and 1917.151(b)(8)).