• Macklanburg-Duncan

• Maier: Ernest Maier

• Mariani & Richards, Inc.

• Martin Marietta Aggregates

• Masonry Technology Inc.

• Master Builders, Inc.

• Matthews Paint Co.

• Metacrylics

• Metalcrete Industries

• Monsey Bakor Inc.

• Muralo Co.

• Nebraska Plastics, Inc.

• Neogard, A Division of Jones-Blair Company

• Nox-Crete Products Group

• O'Leary Paint

• OKON, Inc.

• Osmose Wood Preserving

• Owens Forest Products

• Pecora Corp.

• Permaquik Corporation

• Permasil Company, Inc.

• Pittsburgh Glass Block Company

• Polymer Plastics Corp.

• Polymer Plastics Corp. Vitricon Div.

• Pro-Seal Products

• Professional Products of Kansas