by Sally Colby
Anyone with a pesticide applicator’s license has heard it: the label is the law.
Tracy Harpster, Penn State extension educator, pesticide education program, says labels are not only the law but also include information about the appropriate personal protective equipment (PPE) for that product.
“Labels have changed a lot over the last couple of years,” said Harpster. “They are much easier to read and it’s much easier to find information on labels.”
But if labels are going to be useful, they have to stay on the container. “You’re not supposed to pull them off and put them in a notebook,” said Harpster. “Extra labels are available online — find them and put them in a binder. That way you know what’s going on with the product.”
When it comes to assessing the risk of certain substances, Harpster explains hazard equals toxicity times exposure. “Hazard refers to the risk or potential for harm to you, to others, the environment,” she said. “Toxicity is the active ingredient in the product. You cannot change the toxicity but you can change exposure. Exposure is how the active ingredient in the material gets onto you, whether it’s direct or indirect.” One of the most effective ways to reduce exposure is with the use of proper PPE.
Harpster says if the user can minimize exposure, the hazard is reduced even with highly toxic pesticides. “Exposure means getting materials on you, either directly or indirectly,” she said. “Direct exposure is getting the material on yourself through spray mist, drift or accidental exposure during mixing and loading or cleaning nozzles. Indirect exposure is when the material is on equipment or the material is on your footwear or other clothing.”
Pesticide residue is also part of the equation. “Residue is leftover material,” said Harpster. “Whether it’s on the crop, on your tank and equipment or on your clothes. But when you take your booties off, when it ends up on your hands, you’re exposed.” Harpster reminds applicators to always be aware of where residue might be and to avoid short-cut mistakes such as using teeth to remove gloves.
Pesticides can enter the body in four ways: through the eyes, skin, nostrils and mouth. “The new Worker Protection Standard (WPS) requires any exposure of the eyes [to have] irrigation of the eyes for a full 15 minutes,” said Harpster. “If the water for irrigation is only sufficient for part of that time, flushing must be continued with additional water.”
The eyes contain numerous blood vessels and are moist. “Pesticides can move very quickly into your body through the eyes and there’s also the issue of eye damage,” said Harpster. “The two best ways to avoid getting materials into the eyes is by wearing safety glasses and keeping your fingers out of your eyes.”
Harpster reminds chemical applicators the skin is the largest organ of the body and the body absorbs materials at different rates. If material is on a part of the body where the skin is thin or the blood vessels are very close to the skin surface, the material will move into the body faster. Harpster says 97 percent of all pesticide exposure occurs through the hands, mostly because users don’t wear the proper gloves. Because it’s difficult to open a jug while wearing the appropriate PPE, Harpster recommends using disposable gloves over top of the PPE gloves for a tighter fit.
“Keep your fingers out of your ears,” said Harpster, reminding applicators of a common mistake. “Direct transmission of residue can happen that way. You sweat a lot, you might be wearing a ball cap and materials can move through that. Your feet in rubber boots sweat a lot, and pesticides can move quickly through the socks to the soles of your feet.”
Inhalation exposure involves more than the initial damage which can occur to the nostrils, esophagus and lungs. Once the material has entered the lungs, the blood vessels in the lungs carry pesticides rapidly through the body. “Insecticides are likely to be more damaging because we are closest to the insect we’re trying to control,” said Harpster. “The active ingredients in those pesticides are going to cause more damage than some of the other materials, but we still need to be cautious with all materials.”
Harpster says the greatest danger of pesticide damage to children is through oral ingestion when material has been transferred for storage to a container which is a familiar drink container. Mixing and loading chemicals often poses an additional risk simply because there might be pollen or other irritants in the air which make it tempting to use fingers in eyes, nostrils or ears. “Wash your hands before you eat, before you put a chew in and before you use the bathroom,” said Harpster. “Even if it’s only Roundup — wash your hands.”
Toxicity from exposure to farm chemicals can be acute and/or chronic. Acute toxicity is a one-time severe event while chronic toxicity is a long-time buildup after numerous exposures. Harpster compares chronic exposure to being stung by bees — the first time or so might not cause a severe reaction, but reactions become increasingly severe and lead to the potential for anaphylactic shock. “Toxicity is determined by LC 50,” she said. “That’s lethal concentration, or how much it takes to take out 50 percent of the population. It’s based on milligrams per kilogram. The signal words we have on our herbicide, insecticide and fungicides are based on that toxicity.”
Harpster urges growers to always wear the appropriate PPE during mixing and loading because the chemicals are more concentrated during this time. Always follow mixing and loading instructions carefully, especially when using water soluble packets.
Test gloves by filling them with water and checking for leaks. If they leak, even just a tiny bit, throw them out. Keep all PPE in good shape. Harpster says a Tyvek suit is good for one application, or eight hours, and should be discarded after that time period. “We usually have to wear these when it’s hot outside,” she said, “so they stink pretty bad by the time you’re done with them.”
It’s important to separately launder any clothing which has been worn while applying pesticides and herbicides. “Wash them twice,” said Harpster. “Use a heavy-duty cycle and hot water. You want to break down the active ingredient and rinse it away.” Harpster added hanging laundry outdoors to dry is beneficial because sunshine helps break down some chemicals such as pendimethalin. “You don’t want this stuff on your underwear or socks, or on your kids’ underwear or socks,” she said. “Run an extra cycle to rinse the machine after laundering clothing that has been worn for pesticide or herbicide application.”