A lawsuit seeking to be certified as a class action has been filed on behalf of consumers in New York and California against the owner of Quaker Oats after testing found traces of the pesticide glyphosate in some oatmeal.

While the level of glyphosate, the active ingredient in the popular weed killer Roundup, detected in the oatmeal falls well below the limit set by federal regulators for human consumption, the lawsuit accuses Quaker of false advertising because it markets the oatmeal as “100% natural.”

Quaker, which is owned by PepsiCo, says on its website that the oats used in its products are grown in an environmentally responsible way. “Since oats require less herbicide spray than many other grains, there is less risk of pollutants and groundwater contamination,” it says.

The lawsuit, filed in Federal District Courts in New York and California, contends that such statements are false and misleading. “There is nothing unlawful about Quaker Oats’ growing and processing methods,” the suit says. “What is unlawful is Quaker’s claim that Quaker Oats is something that it is not in order to capitalize on growing consumer demand for healthful, natural products.”