Bayer, BASF and Dow Chemical have confirmed that they have been subpoenaed by the U.S. Department of Justice (DoJ) in an investigation of alleged anti-trust activities by polyurethane chemical producers. The probe concerns possible price fixing in the methylene diphenyl di-isocyanate, toluene di-isocyanate and polyols markets. In a filing with the U.S. Securities and Exchange Commission, Bayer said it is facing allegations of price fixing in multiple civil law suits. Those suits, whose plaintiffs are seeking class-action status, have been consolidated in a federal district court in Kansas. BASF said it was unaware of any violations and would cooperate with investigators but added that it would not comment further because the case is ongoing. Dow, too, said it plans to cooperate fully with the DoJ. “It is our hope that this investigation will move forward quickly and resolve any concerns about Dow’s participation in these markets,” the company said in a statement.