Which engineering control is an alarm, a warning light, or a verbal "countdown" command can be used during activation or startup?

• A. WARNING SYSTEMS
• B. NOMINAL HAZARD ZONE (NHZ)
• C. REMOTE OPERATION
• D. MASTER SWITCH CONTROL

Answer: (A)

Warning systems are an engineering control that communicates risk during activation or startup through alarms, warning lights, or verbal countdowns. These cues alert personnel to unsafe conditions and guide them to pause or take corrective action before the process proceeds, helping ensure a safe start. The other concepts describe different ideas: the nominal hazard zone identifies where exposure could occur rather than how to manage startup, remote operation refers to where control is executed rather than how warning is conveyed, and a master switch control is simply a way to start or stop equipment, not an integrated warning mechanism.