PORTLAND, Ore. » The discovery of genetically-modified wheat in an Eastern Oregon field has touched off a debate on the economics and safety of altering crop genetics.

Critics of genetic modification point to a study that estimates the wheat industry stands to lose $94 to $272 million annually if genetically-modified wheat is introduced.

The USDA announced the discovery of the Monsanto-owned strain on Wednesday. It led to Japan postponing a 25,000-ton order from a Portland grain shipper.

Unapproved genetically-modified rice found in a 2006 U.S. harvest led to plunging rice prices and payments from the offending company to American farmers, the Oregonian reported.

Monsanto tested glyphosate-resistant wheat in 16 states, including Oregon, from 1998 to 2005. The last Oregon trial was in 2001, according to the USDA, and Monsanto ultimately withdrew its application to have the modified variety approved after it became clear export markets didn’t want it.

The company said it closed the testing program in a “rigorous, well-documented and audited” process that should have left no modified plants or seed remaining.

To ensure the plants didn’t emerge after the testing, modified seeds were burned, buried six feet underground or shipped back to Monsanto, said Bob Zemetra, a crop scientist who worked on the Monsanto fields in Idaho.

Wide “no-plant” areas were maintained around test sites to prevent pollen movement from the modified wheat to other crops. Testing sites were checked two years after the trials for the presence of “volunteer” wheat plants that might have popped up.

Center for Food Safety attorney George Kimbrell said Monsanto may be liable for damages if Oregon wheat growers or shippers lose sales. Kimbrell said it’s unreasonable to expect genetically-modified plants to be controlled, especially when they are being tested near commercial wheat operations.

“Nature finds a way,” Kimbrell said.

Kimbrell and other critics say U.S. regulation of genetically modified crops is weak, with regulators relying on company data and inadequate monitoring of the plants’ geographical spread, particularly after testing is complete.

U.S. Sen. Jeff Merkley of Oregon is trying to repeal the so-called “Monsanto Protection Act,” a rider attached to a stopgap funding bill in March that strips federal courts of the ability to require more safety review for some genetically modified seeds.

Investigators have not publically ruled out any possibilities as to how the modified wheat entered a commercial field. Zemetra said accidental seed contamination is possible, but the questions of how and when may be impossible to answer.

“There’s a lot of fear,” he said. “And this isn’t going to help, I can tell you that.”