Must be conscious of safety methods to avoid injury to others and themselves; mitigation of emergencies may involve performing hazardous tasks requiring strenuous physical exertion for extended periods of time in cramped surroundings, hot, smoky environments with limited visibility, and at considerable heights; work in dark, confined, disorienting spaces; work in overheated environments; work under adverse and stressful conditions; employees may find themselves in hostile or psychologically demanding environments, involving emotional or psychological stress work in unpredictable emergency situations for prolonged periods of physical exertion without the benefit of warm-up, scheduled rest periods, meals, access to medication(s), or hydration. Vocal communication is required for expressing or exchanging ideas by means of the spoken word, and conveying detailed or important instructions to others accurately, loudly, or quickly; hearing is required to perceive information at normal spoken word levels, and to receive detailed information through oral communications and/or to make fine distinctions in sound; visual acuity is required for depth perception, color perception, night vision, peripheral vision, preparing and analyzing written or computer data, visual inspection involving small defects and/or small parts, use of measuring devices, operation of machines, operation of motor vehicles or equipment, determining the accuracy and thoroughness of work, and observing general surroundings and activities.