Purolite started in a chemist's basement over 40 years ago. Since then, it has grown to a $400 million-a-year, 1,000-employee business making resin beads used to reduce impurities in the pharmaceutical and other industries.

Now, St. Paul-based Ecolab is buying the Pennsylvania company, which is still family-run, for $3.7 billion.

Ecolab Chief Executive Christophe Beck on Friday said the company adds a double-digit growth opportunity for the company's life sciences division with products that have high profit margins.

"We are building a major new growth engine for our company, as we did with water a decade ago," Beck said during the webcast.

Company founders Steve Brodie, 81, and his brother Don, 76, whose basement was used in creating the resins, have agreed to stay on through the transition.

Ecolab's existing life sciences business — with products for cleaning and sanitation control concentrating on production environments — will produce about $270 million in revenue in 2021, according to the investor presentation for the deal.

Purolite's products offer chances to expand contracts because its microscopic beads are used to purify, separate and decontaminate solutions used in a variety of applications including the manufacturing of drugs and vaccines, computer chips, foods and beverages, mining and in the nuclear power industry that ensures end-product quality.

The acquisition also adds geographic reach, with manufacturing plants in Europe, Asia and Latin America.

John McNulty, an analyst with BMO Capital Markets, wrote in a research note that the two companies' teams "should be able to leverage each other" to increase sales.

Hayley Crowe, Ecolab's current head of the life sciences business, will run the combined operations after the close of the transaction.

Multiple Brodie generations have worked at the company, which has developed more than 1,000 commercial products since Don Brodie, executive vice president of operations and development, created the first product. Steve Brodie served as president and CEO.

Ecolab announced the deal for Purolite after the market closed Thursday; on Friday the company's shares closed at $222.20, up less than 1%.