Four European and American fragrance makers must face lawsuits accusing them of conspiring to inflate prices of ingredients used to make cosmetics, cleaners and other household products, a federal judge in New Jersey has ruled.

U.S. District Judge William Martini on Friday rejected efforts by the companies — Switzerland-based Givaudan and Firmenich, which has merged with DSM Group; U.S.-based International Flavors & Fragrances and Germany’s Symrise — to dismiss three proposed class action lawsuits filed in 2023 by consumers and other buyers.

The lawsuits, alleging an illegal price-fixing conspiracy, came after EU investigators in 2023 announced an antitrust investigation of some major fragrance makers.

The judge dismissed some state-based allegations but will allow those plaintiffs to file an amended lawsuit within 30 days.

Givaudan, Symrise and International Flavors & Fragrances did not immediately respond to requests for comment. DSM-Firmenich in a statement on Monday said it was cooperating with previously disclosed investigations by U.S. and European competition authorities. The companies have denied wrongdoing.

Attorneys for buyers did not immediately respond to similar requests.

Martini is presiding over cases filed by consumers, companies that purchased products directly from the defendants, and “indirect” buyers that purchased fragrance ingredients and compounds from sellers other than the defendants.

Sales of fragrance ingredients reached $9.1 billion in 2022, according to the plaintiffs, who alleged that the fragrance market was highly concentrated and “more susceptible to collusion and other anticompetitive practices.”

The fragrance companies in seeking dismissal of the lawsuits argued that the plaintiffs failed to offer adequate evidence of a conspiracy to fix prices.

“The ambition of plaintiffs’ claims stands in sharp contrast to the paucity of their factual allegations,” the companies told the judge.

They said the lawsuits were “based on nothing more than reports of government inquiries into the fragrance industry.”

European antitrust investigators said in June 2024 that their fragrance industry probe was ongoing.

The cases are In re: Fragrance Direct Purchaser Antitrust Litigation, U.S. District Court for the District of New Jersey, No. 2:23-cv-02174-WJM-JSA; In re: Fragrance Indirect Purchaser Antitrust Litigation, No. 2:23-cv-03249-WJM-JSA; and In re: Fragrance End-User Plaintiff Antitrust Litigation, No. 2:23-cv-16127-WJM-JSA.