Hot tubs

MDI, based in Minneapolis, has produced millions of tubs for USPS. Image: Minneapolis-St. Paul Business Journal

Ever wonder where plastic flat tubs come from?

The Minneapolis-St. Paul Business Journal recently went behind the scenes at a company that has produced millions of tubs for USPS.

Minnesota Diversified Industries (MDI), a Minneapolis-based nonprofit company, has supplied the Postal Service with tubs and corrugated plastic packages since the 1990s. The company also produces custom packaging boxes for several Fortune 1000 firms.

MDI recently began using polypropylene — a tougher, more durable material — to manufacture the tubs and other plastic containers.

“We believe this will be transformative for this company. It is our next best thing,” Barbara Majerus, an MDI vice president, told the newspaper.

The company — which has five locations in Minnesota and employees more than 500 people, including 260 with disabilities — expects to generate $36 million in revenue this year.