Experience and Excellence Leads to Success


Dave Fabianski

Chief Executive Officer

Dave is widely regarded for his authentic, inspirational leadership style and his achievements leading strategic growth, business transformation, and organizational success. As CEO, Dave blends strategic vision with a pragmatic, disciplined approach to business execution; an unwavering focus on customer excellence; and a commitment to maintaining a healthy culture and a talented, vibrant, and engaged workforce. Prior to Apex, Dave served as President of Rite-Solutions, Inc. and Senior Vice President & General Manager at Vangent, Inc. He holds an MBA from Northeastern University and a BS in Workforce Development and Education from Southern Illinois University. He also served honorably for 10 years with the US Naval Submarine Force and continues his affiliation with the armed forces as a member of the Veteran Mentor Network and Homes For Our Troops. In his free time, Dave enjoys volunteering with USA Hockey, supporting Autism Speaks, and spending time with his wife and three children.


Darwin L. Nelson, PE

Chief Operating Officer

Darwin brings 30 years of experience in operational leadership, organizational effectiveness, and strategic growth. As COO, he leads the company’s nationwide business operations across multiple geographies, end markets, and service areas. He is responsible for ensuring Apex operates in a highly effective, safe, and efficient manner while aligning people, processes. and culture to deliver exceptional client satisfaction and sustainable growth. Prior to Apex, Darwin served as President of Tetra Tech AEG and previously as President of CDM Smith’s North America Unit. He is a registered Professional Engineer with a BS in Civil Engineering from Arizona State University. Darwin enjoys spending his leisure time outdoors—hiking, camping, fishing—and quality time with his three sons.


Brian Burke

Chief Financial Officer

Brian brings over 30 years of financial management experience spanning risk management, financial reporting, strategic planning, and mergers and acquisitions-expertise he uses to help Apex strengthen its traction in the marketplace. Before joining Apex, he served as the Chief Financial Officer and Executive Vice President for Archway Marketing Services. Prior to that, he served as the Vice President of Corporate Development for Snyder Communications where he led the due diligence and negotiations for myriad complex transactions. Brian began his career in public accounting with Arthur Andersen where he earned his CPA designation. He holds a BS degree from Virginia Tech and when he's not working, he enjoys spending time with his teenage son and daughter.


Todd Musterait

Chief Growth Officer

Todd is a highly respected leader and growth strategist with over 25 years of experience in environmental consulting and engineering services. As CGO, he leads Apex's strategic growth initiatives across the firm, overseeing all aspects of organic growth and corporate development. Prior to Apex, Todd served as Chief Strategy and Growth Officer of Environment for AECOM, and previously as President of Ecology and Environment, Inc. He is a licensed Professional Engineer in four states with a ME in Civil Engineering from Clarkson University and a BS in Civil Engineering from the University of New Hampshire. Todd is active in industry associations and local engagements, including most recently serving as a board member for the nonprofit Western New York Sustainable Business Roundtable. Todd resides in New York where he enjoys spending time with his wife and two daughters, being outdoors, and physical fitness activities.


Pam Semler

Executive Director, Human Resources

Pam, a seasoned human resources (HR) professional with over 30 years’ of multi-faceted experience, provides management and oversight of our HR organization and development and execution of our HR strategy. Tapping a diverse background and extensive experience, she addresses emerging business drivers and organizational issues, while balancing the needs of our employees and the dynamics of a growth-oriented workplace. Prior to joining Apex, Pam served in HR management positions with General Dynamics Information Technology, Vangent, Inc., Interactive Media Corporation and its predecessor companies; as well as in consultative roles with IBACOS and Rite-Solutions. When she's not working, Pam enjoys landscaping, “farm to table” cooking, designing cards and invitations, and above all, spending time with her family and grandchildren.

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