Wisconsin Department of Agriculture, Trade and Consumer Protection: Inspect Poly Tanks Every Spring and Fall

MADISON – Agriculture officials are reminding farmers to routinely inspect polyethylene tanks used to store fertilizer and pesticides, after several recent failures led to chemical spills. 

“Last year 4 out of 39 reported agrichemical spills were caused by poly tank failures, and so far this year that number is 4 out of 35 spills,” says Rick Graham, spills response coordinator for the Wisconsin Department of Agriculture, Trade and Consumer Protection. “These tanks do have a ‘shelf life’ and you need to inspect them at the beginning and end of the season.” 

Cleanup is costly, requiring removal of the contaminated soil and either land spreading or landfilling it. The farmer is responsible for cleaning up any contaminated soil, although some cleanup costs may be reimbursed through the Agricultural Chemical Cleanup Program. 

Polyethylene tanks may be placed in fields for the growing season, or they may be mobile –pulled on carts or placed in the bed of a truck. They are extremely common, because they are readily available, relatively low cost, and resistant to corrosion. But they are susceptible to weathering, especially if they are always outdoors in sunlight. UV radiation from the sun breaks the material down. They become brittle and may split open, spilling the contents. 

Estimates for shelf life vary from 12 to 18 years, depending on where the tank is kept and how it was designed, but tanks may start showing signs of UV damage after 5-8 years. 

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 to the eye or noticeable to the touch. 

You can test for crazing by rubbing a water-soluble marker over small sections of the tank and then wiping it off with a dry cloth. If crazing has occurred, ink will have soaked in and made it visible. 

Another test is to simply hit the empty tank with a baseball bat, he says. It sounds extreme, but a tank that is sound will not be harmed, while one that cracks was already unsafe. 

Any agrichemical spill must be reported as soon as it is discovered, by calling 1-800-943-0003. This number is answered 24 hours a day. For more information about agrichemical storage and spills, visit datcp.wi.govand search for “spills”.