Emergency stops

Scope

OSHA does not have a comprehensive regulation on e-stops. Rather, there are several machine-specific regulations that address e-stops to varying degrees, as well a general requirement to keep workers safe around moving machinery.

Regulatory citations

There is no specific standard for emergency stop controls. However, several standards do address them to varying degrees:

• 29 CFR 1910.144(a)(1)(iii) — Safety color code for marking physical hazards
• 29 CFR 1910.216 — Mills and calendars in the rubber and plastic industries
• 29 CFR 1910.217 — Mechanical power presses
• 29 CFR 1910.261 — Pulp, paper, and paperboard mill conveyors
• General Duty Clause of the OSH Act

Key definitions

• E-Stop: Emergency stop devices are designed to be used in reaction to an incident or hazardous situation and, as such, are not considered machine safeguarding. These devices, such as buttons, rope-pulls, cable-pulls, or pressure-sensitive body bars, neither detect nor prevent employee exposure to machine hazards; rather they initiate an action to stop hazardous motion when an employee recognizes a hazard and activates them.

Summary of requirements

Employers must:

• Assess machinery for necessity of e-stops. Most new equipment will have the features built-in. Some OSHA standards, such as those for mechanical power presses, specifically require an e-stop. Most dangerous equipment where workers could be caught, trapped, or otherwise injured, should have an e-stop.
• Ensure e-stops are installed and maintained properly. Equipment manufacturers generally provide this information.
• Ensure the e-stops are within immediate reach of operators who may be exposed to dangerous moving parts.
• Color e-stops red. Backgrounds should be yellow.
• Do not place rings or shrouds around e-stops such that intentional actuation could be interfered with. OSHA says that sufficient clearance must be maintained so as not to impede the intentional operation of the control. [Sufficient clearance is recognized as a clear surface area of 120mm diameter centered on the actuator (approximately 4 3/4 inches) with nothing in this area extending above the plane of the actuated (pressed) button.]