LEWISTON — CES Inc., a Brewer-based engineering firm, has acquired Lewiston-based Summit Environmental Consultants, according to MaineBiz.

The terms of the deal were not disclosed.

Summit has 20 employees and offices in Lewiston, Augusta and Bangor. Summit will operate as a subsidiary of CES, and will maintain its offices in Lewiston and Augusta. Employees at Summit’s former Bangor office have moved into CES’ headquarters in Brewer, according to MaineBiz.

Summit, founded in 1994, was co-owned by Michael A. Deyling and James W. Bouquet, according to the company’s website. The company offers public- and private-sector clients expertise in geology, hydrology, engineering, industrial hygiene, geosynthetics, hazardous materials testing and construction materials testing.