The International Union of Operating Engineers (IUOE) is a progressive, diversified trade union that primarily represents operating engineers, who work as heavy equipment operators, mechanics, and surveyors in the construction industry, and stationary engineers, who work in operations and maintenance in building and industrial complexes, and in the service industries. IUOE also represents nurses and other health industry workers, a significant number of public employees engaged in a wide variety of occupations, as well as a number of job classifications in the petrochemical industry.

Tower Rock Stone Company Inc is a construction company based out of 250 W Sand Bank Rd, Columbia, Illinois, United States.

The Missouri State Employees'​ Retirement System (MOSERS), established September 1, 1957, is governed by the statutes of the state of Missouri. MOSERS is a statewide public pension fund providing retirement, disability and survivor benefits for approximately 100,000 state employees, retirees, and their families.

Interactive Management, Inc. (IMI) is a full service accredited association management company. Association management companies enable all organizations to enjoy the benefits of professional management. At IMI, we work as a team to ensure the value and success of our client's programs. Our role is to manage the activities of our clients and help them realize their goals and objectives with the guidance of their board of directors. This allows volunteers to concentrate on program development, not administrative detail.

Kilian Engineering, Inc specializes in mechanical, electrical, plumbing and fire alarm engineering and design.

Robinson Construction Company is a design-build general contractor providing EPC, design-build, construction management, and general contracting services throughout the entire United States. Robinson Construction completes projects, large and small, for a variety of specialized markets including commercial/institutional, energy, food & beverage, government/public, healthcare, heavy civil/water, industrial & process, manufacturing, marine, and mining industries. Founded in 1946, Robinson is headquartered in Perryville, Missouri with a regional office in Hopkinsville, Kentucky.

Christ Brothers Asphalt Inc is a construction company based out of P.O. BOX 158, Lebanon, Illinois, United States.

J.H. Berra Construction Co., Inc. is a construction company based out of 5091 NEW BAUMGARTNER RD, Saint Louis, Missouri, United States.

Highway and bridge construction.

Keller, Inc. was started and incorporated in the State of Wisconsin in 1960. The company is headquartered in Kaukauna with offices in Madison, Milwaukee and Wausau. Over the years the company has developed into the leading Design/Build General Contractor throughout the state. Presently, we employ approximately 260 people, both office and field personnel. Walter Keller was the founder of the company and was the President from inception until 1989 when he was named Chairman of the Board. The current officers are Cory VandeWettering – President, Steve Klessig – V.P. Architecture and Engineering, Craig Otis – Senior V.P. of Construction, and Douglas Stecker, CPA – V.P. Finance/CFO. In 1986, Keller started an Employee Stock Ownership Plan (ESOP) to initiate a planned transfer of ownership to its employees and the company is now 100% owned by the ESOP. This concept results in increased dedication and responsibility assumed by all employees throughout the building process and subsequently a more professional product for our clients. Keller has served the agricultural, automotive, assisted & senior living, child care, chiropractic, cold storage, construction management/municipal, convenience store, dental clinic, education, faith-based, financial, funeral home, hospitality, industrial, medical, professional office, recreation, manufacturing, restaurant, retail, veterinary and warehouse markets.

Kozeny-Wagner provides general construction, design-build and construction management services. Our focus revolves around commercial, academic, healthcare, retail, industrial and civil construction projects. The company was founded in 1965 and is based in St. Louis, Missouri.

Established in 1997 with the goal of becoming the best site utility contractor in the St. Louis area, we have honed our expertise in Mass Earthwork, Land Clearing, Demolition, Land Development, Site Grading, and Site Finish Grading. Over the past 20 years, our team has grown from 10 to 70 talented members, has been nominated for Best Specialty Contractor of the Year, and was a featured contractor in Industry Scoop. We are also fully bonded and are licensed within numerous counties and municipalities.