Monson Companies, Inc. operates a chemical manufacturing and distribution facility in South Portland, Maine. September 9, 2010, and February 10, 2011 inspections revealed that the company violated EPCRA 312 by omitting over 20 hazardous chemicals present at the facility from its emergency and hazardous chemical inventory (Tier II) form. The facility also violated the general duty clause of CAA 112(r)(1) by failing to separate incompatible chemicals and failing to provide adequate aisle spacing throughout its chemical warehouse. The facility also violated RCRA and the Maine Hazardous Waste Management Rules by failing to conduct hazardous waste determinations and failing to maintain an updated hazardous waste contingency plan.