Eye injuries are the leading cause of blindness among farmers, and eyes are the second most injured body part. Simply wearing the right kind of goggles, or other protective equipment, would prevent most of those injuries.
I've conscientiously worn safety goggles when mixing herbicides for 30 years. But one unexpected event showed me I wasn't wearing them often enough.
It happened when I carried a bag of AMS out of a storage shed and plopped it down on top of a small poly tank partially filled with mixed herbicide. That tank had a vent in the lid, and herbicide solution shot up through the vent into my unprotected eyes when the bag of AMS impacted the tank. I was scared as I flushed my eyes and called the chemical maker's hotline. I was also lucky. Lucky because that particular herbicide wasn't very dangerous and lucky because it was diluted rather than concentrated. (That mishap also reminded me to keep the herbicide labels handy.)
Farmers' eyes are at risk from impact, heat, radiation, and chemical splashes. According to the National Education Center for Agricultural Safety, the most common eye injuries are flying objects, dust particles, chemicals, and sun exposure. Personal protective equipment must be tailored to the threat at hand. This article focuses primarily on the protective eyewear needed when handling herbicides and anhydrous ammonia (NH₃).
Although I wore goggles when mixing chemicals all those years, I'm not sure I always wore the right kind.
There are three types of eyewear that can be used when handling chemicals: safety glasses, face shields, and goggles. Goggles offer the most protection.
1. Safety glasses with sideshields and brow guards are suitable for handling some chemicals that aren't particularly harmful. They rarely meet label requirements for pesticides, however. Because they don't fit snuggly against the face, chemicals can still run into the eyes. Safety glasses are used primarily to protect eyes from direct impact and heat rather than chemicals.
2. Face shields offer a first line of defense against chemical splashes. But most experts stress that they shouldn't be used alone since chemicals can get past them.
“Face shields should not be worn without safety glasses or goggles,” says Frederick Fishel, University of Florida IFAS Extension. “Generally, face shields are worn when it is highly likely that splashing of pesticides will occur.”
3. Goggles come in three types: vented (ventilated), indirect vented, and unvented. In simplest terms, vented goggles protect against impact, indirect vented goggles protect against chemicals, and unvented goggles protect against vapors as well as chemicals.
Those are crucial distinctions when you are selecting goggles for handling pesticides or NH₃.
Chemical goggles are different
There is an important difference between chemical goggles and ordinary safety goggles, says George Maher, a retired North Dakota State University Extension ag safety specialist. “Chemical goggles have a baffled airway that prevents a direct splash from getting inside the goggles. Ordinary safety goggles do not.”