Key Takeaways The chief operating officer of Air Products & Chemicals stepped down as the company formed a new management board. The company said COO Samir Serhan has resigned, effective immediately. Air Products' chief executive officer will lead the new 12-person management board to help implement the company's strategy. Air Products stock was down about 5% in afternoon trading Monday. Shares of Air Products & Chemicals (APD) dropped Monday after the supplier of industrial gases announced that its chief o ...