The potential environmental and financial risks posed by Roundup Ready alfalfa were argued by attorneys again this week – this time in front of the U.S. Supreme Court.

The oral arguments were part of the Monsanto vs. Geertson Seed Farms court case. The company is challenging a district court’s decision to impose an injunction prohibiting the sale and planting of Roundup Ready alfalfa until USDA completes an environmental impact statement (EIS). Monsanto appealed that decision in 2008 and 2009, but lost both appeals. Then the high court agreed to take the case in January. It’s the first genetically engineered crop case ever heard by the high court.

During the arguments and in a post-argument panel discussion hosted by the Environmental Law Institute, Greg Garre, an attorney for Monsanto, claimed the district court judge erred when he ordered the injunction without first finding out if continued planting of Roundup Ready alfalfa would likely cause “irreparable harm.” He said the judge should have held a hearing to gather information from both sides of the issue, but chose not to duplicate the efforts of USDA’s Animal and Plant Health Inspection Service (APHIS), which he ordered to prepare an EIS.

He also claimed the risk of Roundup Ready alfalfa cross-pollinating with conventional alfalfa was “extremely low,” in hayfields, so the injunction should have applied only to seed production. “There is absolutely no evidence in the record whatsoever of any cross pollination from Roundup Ready alfalfa fields to another hayfield,” Garre told the judges. “So the district court’s injunction applies broad-based to hay production and seed production. But at a minimum, we think you have to take hay production out.”

“In the real world, farmers plant both hay and seed alfalfa in many places,” countered George Kimbrell, attorney for the Center for Food Safety (CFS), during the panel discussion. CFS filed the original lawsuit that led to the injunction.

“Alfalfa is pollinated by feral bees that don’t read signs,” said Kimbrell in arguing that the injunction should remain in place. “They fly five miles and cross-pollinate at that distance.”

He said transgenic alfalfa is potentially an “invasive species,” much like the Asian carp that are invading rivers and lakes. “Genetically engineered crops are similar to those when they are illegally approved, and they’re invading our fields in that way,” he said. “And we’ve seen this in other crops. There’s a long list of contamination incidents in other crops.”

A high court decision is expected by June. Attorneys for neither side would speculate on the outcome, although several Supreme Court judges reportedly seemed skeptical of the injunction’s validity. One judge wondered whether the ruling would be moot, since Roundup Ready alfalfa probably will be legalized when the EIS is completed. APHIS published a draft EIS in December and is working on the final document. However, Monsanto’s attorneys said that APHIS now projects that the EIS won’t be ready until this time next year.