The regulations surrounding chemigation have been effectively established by the United States Environmental Protection Agency many years ago. There are two documents that are the cornerstones of such rules and are very informative about labeling requirements and safety devices.
The first link is to Pesticide Registration Notice 87-1 ( PRN 87-1). This notice gave additional compliance rules for all chemical manufacturers with regard to product labeling. A very important concept in this document is: If the label is silent regarding chemigation, then the product is suitable to use with chemigation. Only if it is NOT intended for chemigation must it then be indicated by the following prohibition statement: “Do not apply this product through any type of irrigation system.”
The second important link is USEPA Interim Final FIFRA Compliance Program Policy No. 12.7. This document defines the chemigation safety devices as defined in PRN 87-1 AND alternative safety equipment that could be used in place of such equipment defined in PRN 87-1. In the document, the original devices are listed, followed by the acceptable alternatives. The most commonly discussed device is the “Functional normally closed, solenoid-operated valve located on the intake side of the injection pump” and its typical alternative, a “Functional spring-loaded check valve with a minimum of 10 psi cracking pressure”. This alternative was approved in no small part due to the invention of the Mister Mist’r check valve in the mid 1980’s.
Click here for the link to USEPA Interim Final FIFRA Compliance Program Policy No. 12.7.