The US Environmental Protection Agency (EPA) has asked a federal appeals court time to vacate the agency’s own approval of the Dow AgroSciences herbicide Enlist Duo as it needs time to evaluate new information regarding the product’s toxicity to neighboring crops.

Following Dow’s response to the EPA's motion, the court will decide whether or not to take action.

The environmental watchdog said it has new information that Dow did not provide during the approval, which could lead it to a "different decision" about restrictions on its use. In particular, this could include stricter measures to protect nearby plants.

Enlist Duo was approved by the EPA, with restrictions, in October 2014 for use in six US Farm Belt states, to combat the so-called super weeds that have wreaked havoc on crops in the Midwest. It expanded the approval to an additional nine states earlier this year.

Dow’s newest crop protectant agent has been controversial, especially as it combines glyphosate with 2,4-D, a component of the defoliant Agent Orange used during the Vietnam War.

Dow and supporters of the herbicide have argued that it is needed because the fast-growing super weeds have developed defenses against glyphosate, the active ingredient in a number of commercial herbicides, including Monsanto’s Roundup. Enlist Duo combines glyphosate and a newer version of 2,4-D that Dow says is safer than older versions.

Environmental advocates, however, believe that ongoing reliance on chemical crop protection agents increases the risk that weeds such as palmer amaranth and marestail will develop further herbicide resistance.

Several environmental-advocacy groups, including the National Resource Defense Council and the Center for Food Safety and Earthjustice, sued the EPA last year on grounds it had failed to adequately consider the herbicide's effects on threatened and endangered plants and animals.

At the time, the EPA defended its decision to approve Enlist Duo under restrictions that included requiring Dow to track and report on weed resistance to the product. The agency issued a 30-foot-in-the-field “no spray” buffer zone for application areas and banned the product from use when wind speeds exceed 15 miles per hour. It also agreed to review its approval in six rather than the customary 15 years.

In a statement, Dow said it still expects Enlist Duo to be available for the upcoming 2016 US growing season and continues to prepare for commercial sales of the spray.

In an announcement last March, a group of scientists in the World Health Organization’s International Agency for Research on Cancer (IARC) said they had unanimously decided to classify glyphosate as “probably carcinogenic to humans.” The statement aroused controversy throughout the industry and led Monsanto to demand the decision be rescinded. In June, IARC said it would analyze its findings.