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Occupational Safety and Health, Environmental Protection, and 5S

Industrial Manufacturing (SSW 2) · 製造分野(2号) · Written by Tokutei Pass based on the official study texts; not copied verbatim.

5S Activities, Heinrich's Law, and Risk Assessment

Workplace '5S' consists of Sort (Seiri: discard unneeded items), Set in Order (Seiton: arrange and label for easy access), Shine (Seisou), Standardize (Seiketsu), and Sustain (Shitsuke).

Heinrich's Law states that behind 1 major injury lie 29 minor injuries and 300 near-misses (Hiyari-Hatto).

Hazard Prediction (KY) activities identify risks and countermeasures before work, while Pointing and Calling ('... OK!') prevents human error.

In Risk Assessment, risk reduction follows the hierarchy of controls: Inherently safe design -> Engineering controls (guards/interlocks) -> Administrative controls -> Personal Protective Equipment (PPE).

5S Activities, Heinrich's Law, and Risk Assessment

Key points


  • (○ True) Heinrich's Law ratio is '1 : 29 : 300'; addressing near-misses prevents major accidents.

  • (○ True) Risk reduction prioritizes inherently safe design and engineering guards first, with PPE as the last supplementary measure.

  • (× False) Defining Sort (Seiri) as 'neatly storing unneeded items' or making PPE the highest-priority risk reduction measure is FALSE.
WordMeaning
Sort and Set in Order
Heinrich's Law
near-miss incident (Hiyari-Hatto)
risk assessment
pointing and calling

Machine Safety (Fail-Safe, Fool-Proof, Interlock, and Lockout/Tagout)

A design principle ensuring a machine defaults to a safe (stopped) state when a component fails or power is lost is called 'Fail-safe'.

Preventing hazards even if an operator makes a mistake is 'Fool-proof', and preventing machine operation while a safety guard is open is an 'Interlock'.

During maintenance, repair, or cleaning inside a machine, perform 'Lockout/Tagout' (LOTO) by shutting off power, locking the switch, and attaching a warning tag.

When operating rotating machinery such as a drill press, never wear cotton work gloves because they can get caught and pulled into the rotating spindle.

Key points


  • (○ True) Designing equipment to fail into a safe stopped state is 'Fail-safe', and preventing operator misoperation is 'Fool-proof'.

  • (○ True) Perform Lockout/Tagout (shut off power, lock, and tag) during maintenance, and never wear gloves when operating a drill press.

  • (× False) Disabling safety door interlocks or light curtains to increase work speed is strictly prohibited.
WordMeaning
fail-safe
fool-proof
interlock
lockout/tagout (LOTO)

Chemical Management (SDS, GHS, Local Exhaust) and Oxygen Deficiency Prevention

Before handling organic solvents or chemicals, always check the 'SDS (Safety Data Sheet)' and GHS pictograms for hazards, required PPE, and first-aid procedures.

During organic solvent work, operate local exhaust ventilation and wear an organic-gas respirator (dust masks or saturated canisters beyond breakthrough do not block solvent vapors).

Before entering a confined space such as a pit or tank, measure the atmosphere to verify that oxygen concentration is at least '18%' (and hydrogen sulfide is 10 ppm or less).

Restricted operations such as operating a forklift or slinging loads of 1 ton or more (Tamagake) may only be performed by workers holding the legally required skill training certificate.

Key points


  • (○ True) Check the SDS before using chemicals, and use local exhaust ventilation and an organic-gas respirator for organic solvent work.

  • (○ True) Verify oxygen concentration is '18% or higher' before entering confined spaces, and ensure only certified operators perform forklift or slinging work.

  • (× False) Using a dust mask for organic solvent vapors or continuing to use a respirator canister past its breakthrough time is FALSE.
WordMeaning
Safety Data Sheet (SDS)
organic-gas respirator
local exhaust ventilation
oxygen deficiency
slinging / rigging (Tamagake)

Electric Shock Prevention, Heatstroke, Back Pain Prevention, and Environmental Protection (3R)

Equip electrical tools with earth leakage breakers and grounding, never touch switches with wet hands, and never pass high current through bundled cords (to prevent overheating and fire).

Monitor the WBGT heat index and replenish water and salt regularly; when lifting heavy loads, stand close, bend your knees, and lift with leg muscles to prevent lower back injury.

Wear hearing protection in noisy areas (85 dB or above); for oil or electrical fires, never use water—use dry chemical powder or CO2 fire extinguishers.

Environmental '3R' prioritizes Reduce -> Reuse -> Recycle; industrial waste such as waste oil must be segregated and consigned to licensed processors using a manifest tracking slip.

Key points


  • (○ True) Bend your knees and hold heavy loads close to your body; monitor WBGT and replenish both water and salt in hot workplaces.

  • (○ True) The top priority in 3R is 'Reduce (waste reduction)', and industrial waste disposal must be tracked using a manifest system.

  • (× False) Pouring buckets of water onto an oil fire or an energized electrical fire is FALSE because it spreads the fire and causes electric shock.
WordMeaning
earth leakage circuit breaker (ELCB)
Wet Bulb Globe Temperature (WBGT)
Reduce (waste prevention)
industrial waste manifest

Safety, Pollution Prevention and KYT

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Official references