Granted…. manhole covers don’t sound exciting! Manhole covers have traditionally been made of cast-iron….and been in existence for more than a hundred years. Every city has manholes….the estimate is 200 million in the United States alone.
GMI Composites in Muskegon, MI makes manhole covers. Not cast-iron, but in composite materials. GMI use to be called the button factory. It was started in the 1920’s making buttons! Over the years, the company has evolved into manufacturing moulded composite products. The plant isn’t very striking….yet here is a relatively small company that has taken a very ordinary product and made it better and different….in so doing creating a new market!