An eyewash station is specialized emergency equipment designed to provide immediate first aid for ocular exposure to hazardous materials. When a chemical, particulate, or biological substance enters the eye, rapid decontamination is the primary defense against permanent injury. Understanding the correct duration of use is paramount for preserving vision. The sustained flushing time ultimately determines the outcome.
The Essential 15-Minute Rule
The minimum duration for using an eyewash station after chemical exposure is 15 minutes. This standard is widely accepted as a best practice and is reinforced by regulatory guidelines, such as those published by the American National Standards Institute (ANSI Z358.1). The equipment must deliver a continuous flow of flushing fluid at a minimum rate of 0.4 gallons per minute for this full period.
This prolonged duration is necessary because the continuous stream of water dilutes the hazardous substance and physically washes it away from the eye tissues. For corrosive chemicals, 15 minutes allows the flushing fluid to begin normalizing the eye’s pH level, preventing rapid, irreversible tissue damage. Flushing must begin the moment the eye is exposed and must not be interrupted for any reason.
To ensure a person can tolerate the full decontamination time, ANSI standards specify that the flushing fluid must be tepid, maintained between 60 and 100 degrees Fahrenheit. Water that is too cold or too hot can cause the injured person to stop the flushing process prematurely, which increases the risk of severe injury. Any time less than the required duration is insufficient to fully decontaminate the eye.
Immediate Steps and Proper Flushing Technique
The first action following eye contamination is reaching the eyewash station within a maximum of ten seconds, as irreversible damage can occur quickly. Upon reaching the station, the activation mechanism must be engaged immediately. The mechanism should be operable in one second and designed to provide hands-free operation once activated, allowing the injured person to concentrate fully on the flushing technique.
Once the fluid is flowing, the face must be lowered into the stream to ensure the water contacts both eyes simultaneously. Use the fingers to forcibly hold the eyelids open, allowing the water to irrigate the entire surface of the eye and flow beneath the lids. The eyes should be gently rolled in all directions—up, down, and side to side—to maximize water contact with all tissues.
If the injured person wears contact lenses, they must be removed during the flushing process. Initial flushing should never be delayed to remove the lenses, as immediate irrigation is the top priority. Once the water is running, the lenses should be gently taken out to prevent them from trapping the chemical against the corneal surface.
Recognizing Hazards Requiring Emergency Flushing
Emergency flushing is required for a range of incidents, particularly chemical splashes. Exposures to simple irritants, such as certain soaps or dust, may require a shorter flushing time, but the 15-minute rule is recommended as a safe minimum duration. Corrosive materials, including both acids and bases, are the most serious and demand the full decontamination period.
Alkali substances, or bases (such as drain cleaners or lye), are especially dangerous because they can rapidly penetrate the eye tissue, a process known as liquefaction necrosis. Exposure to strong alkalis may necessitate flushing for 30 minutes or even up to 60 minutes to adequately counteract penetration and dilution. Physical hazards, including metal shavings, wood splinters, or dust particles, also require emergency flushing to dislodge the foreign body and prevent corneal abrasion.
Necessary Medical Follow-Up
Flushing the eye for the prescribed duration is an act of first aid, not a cure, and it must be followed by professional medical attention. An injured person must seek immediate medical examination after the 15-minute flush is complete, even if symptoms appear to have subsided. Some chemicals can cause delayed damage that is not immediately apparent.
The medical team requires specific information to provide appropriate treatment, making it important to identify the hazardous substance involved. If possible, the Safety Data Sheet (SDS) for the chemical should be provided to the attending physician to inform their assessment. A medical professional will assess the eye for corneal damage and determine if any residual chemical or tissue injury requires further treatment.