A proposal by the U.S. En­­vironmental Protection Agency (EPA) to tighten the already-strict ozone standards threatens to impose real and significant costs on farmers while providing uncertainly and unverified benefits to the environment, the Iowa Farm Bureau Federation (IFBF) said last week in a letter to the EPA.

"These stringent new ozone standards also have the potential for damaging economic consequences across the entire Iowa economy and would place serious restrictions on farmers,...