• Air Quality Experts Since 1980


Bison Engineering, Inc began its work in Helena, Montana under Mike Roach, former Chief of the Montana Air Quality Bureau (MAQB), which merged into the Montana Department of Environmental Quality (MDEQ).

The primary focus of this young company was to provide natural resource development companies (mining and timber industries) with expertise in the air quality field, including ambient monitoring, permit applications and air quality assessments for environmental impact statements. The firm grew quickly and soon added stack/source testing capabilities to its list of air quality services.

In the mid-1980s, the staff at Bison tripled, including the addition of Mr. Roach’s successor as company president, Hal Robbins, who was a former MAQB Chief following Mike Roach. During this time, the mix of clients changed dramatically to include commercial building owners and government agencies as well as a wide variety of industrial facilities. Company expansion brought a greater emphasis on involving the staff in ownership and management of the firm including the creation of an employee stock ownership plan (ESOP).

Bison Engineering continued to grow during the 1990s and shifted from asbestos and indoor air quality services to focus on ambient monitoring, permitting, and stack testing services for industrial clients. Jeff Chaffee, former MAQB Chief and current President, joined the company in 1996. In 1999, we opened our Billings office, bringing our services closer to industrial clients located in Central and Eastern Montana.

In 2001, Mike Roach retired from Bison Engineering and the employee stock ownership plan (ESOP) purchased the company, making it an employee-owned company. Bison continued its focus in air quality engineering while broadening its environmental services to support existing clients. In 2004, Bison purchased its previous Helena office.

In 2015, Bison purchased Energy and Environmental Measurement Corporation (EEMC)/Environmental Measurement Research Corporation (EMRC) an emissions testing and monitoring equipment manufacturer, founded in the 1970s. The acquisition added a product line to Bison’s services, which includes custom design and installation of gas flow continuous monitoring equipment. EMRC was founded in 1981 as a response to the increasing demands of new energy production facilities in the west. The addition of EEMC/EMRC and its staff set the stage for a new opportunity for Bison to serve its clients with value-added products and services. It also allowed us to establish an office and client base in Tucson, Arizona.

In 2020, under current Bison President, Chris Hiltunen, P.E., Bison purchased a new building on East Lyndale Avenue in Helena. Mr. Hiltunen was hired at Bison in 1995 and has provided expertise across several different product lines before becoming President at Bison in 2018.

Today, Bison continues to provide outstanding environmental consulting, technical services, and equipment for an expanding base of clients in the west and across the globe. We look forward to carrying our legacy of commitment and service long into the future.

bison engineering