Emergency Eyewash. The first 10 to 15 seconds after chemical exposure are critical. Emergency showers and eyewash units can provide immediate decontamination, helping to prevent more serious injuries. Experts agree the most important first aid procedure for eye contact with hazardous materials is abundant irrigation within seconds. The need for immediate flushing requires the installation of emergency eyewash devices in accessible locations that require no more than 10 SECONDS to reach.