The Wisconsin Department of Agriculture Advises Applicators to Inspect Poly Tanks Every Spring and Fall

By Steve Tomasko, UW PAT Program

Officials from the Wisconsin Department of Agriculture, Trade and Consumer Protection want to remind people to routinely inspect polyethylene (or “poly” for short) tanks they use to store fertilizer and pesticides. Several recent spills caused by defects in tanks have led to chemical spills.

Since 2018 up to the present, 8 out of 74 reported agrichemical spills were caused by poly tank failures. “These tanks do have a ‘shelf life’ and you need to inspect them at the beginning and end of the season,” said Rick Graham, spills response coordinator for WDATCP.

Poly tanks are extremely common because they are relatively low cost and resistant to corrosion. But they are susceptible to weathering, especially if they are always outdoors in sunlight because ultraviolet radiation from the sun breaks down the plastic. They can become brittle and split open, spilling the contents. Estimates for a usable life span for poly tanks vary from 12 to 18 years.

Cleanup can be a costly venture, requiring removal of contaminated soil. The farmer, coop or other commercial applicator is responsible for cleaning up any contaminated soil. However, some cleanup costs may be recouped through the Agricultural Chemical Cleanup Program.

Graham says farmers should check the tanks for any obvious signs of weakness, such as cracks or straps cutting deeply when used to hold mobile tanks in place. A less obvious sign of a problem is “crazing” – a network of fine cracks that may not be visible or noticeable to the touch.

Glenn Nice wrote an article in an earlier PAT CHAT Newsletter detailing how to check tanks for weakness. You can find that article here.

You must report any agrichemical spill (whether from a poly tank or other means) as soon as you know about it by calling 1-800-943-0003. This number is answered 24 hours a day. For more information about agrichemical storage and spills, visit and search for “spills.” There is also a “Spills” chapter in your certification manual.