A new lawsuit is claiming that popular seltzer water brand LaCroix uses synthetic ingredients, despite its “all natural” branding.

The alleged synthetic ingredients include ethyl butanoate, limonene and linalool propionate, according to the class action suit filed last week by Beaumont Costales. The suit is being brought against LaCroix’s parent company National Beverage Corporation in Chicago on behalf of the plaintiff Lenora Rice and” all those injured by the popular sparkling water brand’s false claims to be ‘all natural’ and ‘100% natural.'”

The Beaumont Costales law firm claims the one of the artificial ingredients, linalool, is also used in cockroach insecticide.

In a statement, the law firm says it wants LaCroix to relabel its packaging and award damages to customers who bought the beverages thinking it was “all-natural.”

“The plaintiff Rice, desiring a healthy, natural beverage, was led to purchase LaCroix sparkling water because of the claims made on its packaging, advertising and web site to be ‘innocent,’ ‘naturally essenced,’ ‘all natural,’ and ‘always 100% natural,'” the statement reads. “However, LaCroix in fact contains ingredients that have been identified by the Food and Drug Administration as synthetic. These chemicals include limonene, which can cause kidney toxicity and tumors; linalool propionate, which is used to treat cancer; and linalool, which is used in cockroach insecticide.”

National Beverage Corp. denies the accusations, calling the claims “false and defamatory.”

“The lawsuit provides no support for its false statements about LaCroix’s ingredients,” the Corp. said in a statement. “The United States Food and Drug Administration (FDA) considers ‘natural’ on a food label to be truthful and non-misleading when ‘nothing artificial or synthetic (including all color additives regardless of source) has been included in, or has been added.’ All LaCroix product labels include an ingredient statement indicating each product contains carbonated water and natural flavors. National Beverage stands by that ingredient statement and the fact that all the flavor essences in LaCroix are natural.”

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Write to Gina Martinez at gina.martinez@time.com.