Clyde Ogg – University of Nebraska, Lincoln, Pesticide Safety Extension Educator
Cleaning pesticide spray equipment between crops or after use for the year means exercising precautions. These precautions include using more personal protective equipment (PPE) than when spraying, and possibly more PPE than the label requires. Most pesticides enter the body through the skin, though they can also be inhaled and ingested.
At minimum when cleaning spray equipment, wear goggles or other eye protection, as pesticides are readily absorbed through the eyes and can injure them. Also wear a chemical-resistant apron or Tyvek® suit, water-resistant head gear, and respirator. These are in addition to the standard fare of long pants, long-sleeved shirt, shoes, socks, and chemical-resistant boots and gloves.
As with any activities involving exposure to pesticides:
- Remove contaminated clothing and shower immediately after cleaning equipment. Don’t wait until the end of the day, as any pesticide on the skin surface can be absorbed into the body.
- Keep contaminated clothing separate from other laundry and make sure the person washing the clothing knows the hazards, and also wears protective gloves.
- Wash clothing in the hottest and highest water level possible. Wash more than once if needed. Throw away any clothing soaked from pesticides.
- If the same washer is used for family clothing, run the empty washer through one or more cycles of hot water and detergent before doing regular laundry.
Greg Kruger, UNL weed science and application technology specialist, demonstrates how to clean a field sprayer in this video from UNL’s Pesticide Safety Education Program. Find more than 40 videos on its YouTube Channel, UNLExtensionPSEP.
Kruger notes: As much as 15 gallons of product can remain in the tank after it’s been emptied, due to the volume in the lines and filters. A thorough cleaning can help avoid contamination.
Careless cleanup is a main cause of equipment failure or malfunction. Always clean application equipment immediately after use, as dried pesticides are harder to remove.
Clean pesticide application equipment at a location where any spilled rinsate won’t contaminate water supplies or other crops, and is inaccessible to children and animals. The location may be the same as the mixing and loading site, and should be impervious to water.
Thoroughly rinse equipment with the recommended cleaning agent and carrier, allowing the cleaning solution to circulate through the system for several minutes. Remove nozzles and screens, and flush the sprayer system twice with clean water.
Clean both the inside and outside of the sprayer. Remove screens and strainers, unless strainers are self-cleaning. Check for residues in damaged hoses and replace them if necessary. Pay special attention to sprayer surfaces or components where dried pesticide buildup might occur, including inside the top of the spray tank and any irregular surfaces inside it.
Rinsate from cleaned equipment contains pesticides and must be collected and disposed of properly. Rinsate could be used as a diluent for future mixtures if it is safe and compatible with the pesticide mixture; however, it must not contain strong cleaning agents such as bleach or ammonia. Any rinsate that cannot be applied to a labeled site should be disposed of as you would a waste pesticide.
Commercial compounds are available to aid in tank cleaning. These neutralize and remove pesticide residues, mineral deposits, and rust. They also leave a protective film on tank walls to help prevent corrosion.
Preparing and Storing Equipment
When storing the sprayer, add one to five gallons of lightweight oil such as diesel fuel or kerosene, depending on the size of the tank, before final flushing. As water is pumped from the sprayer, the oil leaves a protective coating on the inside of the tank, pump and plumbing. Remove and store nozzle tips and screens in light oil to prevent them from corroding.
Sprayer engines require additional servicing after pesticide application. Follow directions in the engine owner’s manual.
Store clean, drained application equipment in a clean, dry building. If the sprayer must be stored outside, remove hoses, wipe oil off exterior surfaces, and store inside where they won’t be damaged by ultraviolet light.
For trailer sprayers, put blocks under the frame or axle to prevent flat spots on tires during storage.
For more information, see the Nebraska Extension NebGuide, Cleaning Pesticide Application Equipment (G1770).