Promotions include Zachary B. Berry, P.E.; Zachary D. Bussey; Brett A. Galbraith; Joseph P. Giglio; Cecily M. Sparks; and William 'Bill' Underwood.

Gajwani brings more than two decades of knowledge of New York’s municipal and private water and wastewater market.

Additional promotions include Jon Grant, Jacob Truax, and David Seiling, who were named senior vice presidents.

Mullett, who was named CEO in 2016, continues those duties and takes on his new role as chairman, immediately.

Dodson brings vast knowledge of regional environmental market.

Widenmann has amassed 34 years of experience in the industry in various sales and marketing leadership roles with three major HVAC product manufacturers.

As COO, Schulken will oversee all day-to-day administrative and operational functions and serve as a member of the executive management team, steering the company on its rapid growth trajectory.

These leaders will be expected to drive Stellar’s continued growth in healthcare, military, and institutional construction as well as mechanical services and parts, service, and compressors into 2021 and beyond.

American Testing Inc.’s Michael S. Kelly was named president.

Goris will succeed Timothy McLevish, who will remain with the company until his Feb. 15, 2021, retirement.