WE ARE 100% EMPLOYEE OWNED.
We are 100% Committed to Sharing What we Make with Those that Make it.

WE ARE 100% EMPLOYEE OWNED.
We are 100% Committed to Sharing What we Make with Those that Make it.

  • Leadership Team
  • Board of Directors

Loren Witkin

A creative and focused leader, Loren has 30+ years of experience in the Environmental, Health, and Safety (EHS) industry, both in the public and private sectors, with numerous state, federal, and industry accreditations and certifications to his name. During his career, Loren has served as a panel member, speaker, and presenter on various EHS matters to universities, public agencies, cities, school districts, and industry conferences nationwide. He held tenure at UCLA as one of the first asbestos/lead program managers in California, where he developed policies relating to the identification and remediation of environmental contaminants for 17+ million square feet of property. He is also a founding member of both the California Medical Association Ad Hoc Committee on Lead and the California Chapter of the National Lead Abatement Council, where he currently takes an active role in the advancement of community awareness for lead poisoning.

Aside from his current CEO duties, Loren devotes his time to sitting on the City of Hope’s LA Real Estate Council, the Downtown Breakfast Club, AJU’s Real Estate Executive Council, and the Central City Association.

Simon Turner

Simon Turner was CEO of Healthy Buildings, until June of 2019. He joined Healthy Buildings in 1987 after sales and research experience in the UK and South Africa. Healthy Buildings was sold to Underwriters Laboratories (UL) in June of 2019 at which time he resigned his post to consult as Founder of Building Cognition LLC, advising growing firms in his field.

Turner is an SME in a wide range of indoor environmental disciplines and has a special interest in the relationship between indoor environments and productivity/human cognition. He has been on various global green building technical and steering committees. He currently serves on the BoD for the Green Building Initiative, operators of the GreenGlobes® sustainability programs, and on the Advisory Board for SafeTraces®, among other Board positions. He is a Life Member of the Building Owners and Managers Association (BOMA).

Jeff Mistarz

Mr. Mistarz has over 25 years of experience as a CFO guiding rapidly growing, small and mid-sized private and public companies, including a private equity-owned civil engineering firm ranked as the fourth fastest growing firm in the US for two years in a row and 14 years at a NASDAQ listed company. Over his career, Jeff has completed numerous financing transactions of all different forms and multiple M&A transactions.

Jeff is responsible for Citadel’s reporting, financing, M&A, and growth strategy formulation.

Connect with Citadel EHS 

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Loren Witkin, CAC, CDPH, LEED AP

CEO

Loren founded Citadel with the goal of creating an employee- and client-focused consulting firm that fused a thorough understanding of the built environment within the fields of environmental, health, and safety.

As part of his vision to bring all employees into ownership roles, Loren drove the formation of the firm’s ESOP in 2003 while simultaneously overseeing all phases of corporate development, client management, and complex project management across multiple disciplines.

A creative and focused leader, Loren has 30+ years of experience in the Environmental, Health, and Safety (EHS) industry, both in the public and private sectors, with numerous state, federal, and industry accreditations and certifications to his name. During his career, Loren has served as a panel member, speaker, and presenter on various EHS matters to universities, public agencies, cities, school districts, and industry conferences nationwide. He held tenure at UCLA as one of the first asbestos/lead program managers in California, where he developed policies relating to the identification and remediation of environmental contaminants for 17+ million square feet of property. He is also a founding member of both the California Medical Association Ad Hoc Committee on Lead and the California Chapter of the National Lead Abatement Council, where he currently takes an active role in the advancement of community awareness for lead poisoning.

Aside from his current CEO duties, Loren devotes his time to sitting on the City of Hope’s LA Real Estate Council, the Downtown Breakfast Club, AJU’s Real Estate Executive Council, and the Central City Association.

You can reach Loren at: lwitkin@citadelehs.com.

Kier DeLeo, CHMM

COO & Practice Leader, Building Sciences

Kier DeLeo is the Chief Operating Officer of Citadel EHS, appointed effective January 1, 2025. In this role, Kier oversees the firm’s operational functions and leads Citadel’s Strategy & Planning Team, driving operational excellence and aligning business performance with strategic growth initiatives. His visionary leadership and deep industry knowledge continue to shape Citadel’s trajectory as a leading environmental, health, safety, and sustainability firm.

Kier joined Citadel in 2015 as the Principal of our industry-leading Building Sciences Group. With over 25 years of experience in the environmental consulting and contracting field, he has played a pivotal role in elevating the practice to national prominence. As Principal, he has led efforts to develop and implement long-term strategic goals for the group, drive revenue, recruit and grow high-performing teams, identify new markets, and ensure the consistent delivery of the Citadel brand.

Kier’s technical expertise includes Building Sciences-related work, Industrial Hygiene, moisture intrusion, environmental due diligence, and subsurface investigations. He has conducted numerous indoor air quality assessments, property transfer investigations, and studies in microbial contamination, noise, and toxic exposures. His broad experience also includes the design assistance of remediation plans, emergency response, facility-wide inspections for compliance and hazards, and plan/specification design for industrial ventilation systems.

He has assisted clients with the development of comprehensive health and safety compliance programs, performed process hazard analyses, and delivered training courses on a variety of occupational and environmental hazards.

Kier is a recognized business leader, known for growing companies and practices through increased sales and client focus, process improvements, market expansion, and effective team development. He drives organizational change through a collaborative leadership style rooted in strategic insight and practical execution.

You can reach Kier at: kdeleo@citadelehs.com

Jeff Mistarz

CFO

Mr. Mistarz has over 25 years of experience as a CFO guiding rapidly growing, small and mid-sized private and public companies, including a private equity-owned civil engineering firm ranked as the fourth fastest growing firm in the US for two years in a row and 14 years at a NASDAQ listed company. Over his career, Jeff has completed numerous financing transactions of all different forms and multiple M&A transactions.

Jeff is responsible for Citadel’s reporting, financing, M&A, and growth strategy formulation.


You can reach Jeff at: jmistarz@citadelehs.com.

Scott Brehmer, MPH, CIH, CSP

Practice Leader, Industrial Hygiene & Safety

Scott joined Citadel in 2017 to lead our Industrial Hygiene and Safety practice areas. With over 20 years of consulting experience, serving in both technical and leadership roles, Scott adds important strategic and management consulting capabilities to the team. As the department leader, Scott provides vision for the future and inspires excellence in the present. He is particularly focused on delivering purpose-driven quality work, ensuring client satisfaction, and supporting the professional growth and well-being of his staff.

As a Certified Safety Professional (CSP), Scott is best known for his ability to assess “all things safety” including culture, management processes, and safety performance of organizations. He supports all industries but is widely respected for his expertise in higher education including the University of California and California State University systems. Much of his career has been dedicated to improving laboratory safety and chemical hygiene on California college campuses.

As a Certified Industrial Hygienist (CIH), Scott is an expert in protecting worker health. He excels in hazard recognition, industrial hygiene program development, exposure assessment, control strategies, and personal protective equipment (PPE) determinations. Scott believes in providing practical solutions that reduce employee exposure and have minimal impact on business operations and productivity.

Scott seeks out clients that value employee health and safety and is passionate about helping companies improve performance and gain or maintain compliance.

You can reach Scott at: sbrehmer@citadelehs.com.

Nalinna Rasu, CAC, CDPH, CHMM, LEED AP

Practice Leader, Environmental Compliance

An expert in the environmental industry since 2004, Nalinna has a broad range of technical specialties that focus on maintaining and promoting the health of those within a built environment, including environmental compliance; hazardous materials and waste management and inventorying; storm water sampling; air emissions reporting and permitting; asbestos and lead materials management; indoor air quality testing, both non-LEED and LEED; chemical exposure sampling; microbiological investigations; and NPDES permitting.

She has extensive experience in developing business and contingency plans for hazardous materials management (CUPA) and spill prevention (SPCC), as well as overall project management experience in conducting surveys for environmentally-regulated materials such as asbestos-containing materials, lead-based paint, PCBs, universal wastes, and Ozone Depleting Substances. A key component of this includes conducting on-site environmental compliance investigations to identify and assess existing hazardous materials that may be impacted by renovations and/or demolition projects.

You can reach Nalinna at: nrasu@citadelehs.com.

Julie Wojnowski

practice leader, esg & Sustainability

Mrs. Wojnowski comes to Citadel EHS after working 10-years with the International WELL Building Institute (IWBI). She also has 10+ years’ experience as a nurse. She’s based just outside of Charlotte, NC. Julie is an expert in the WELL Building Standard (WELL), human health, healthcare, business and revenue operations, third-party professional accreditation (ISO/IEC 17011), and third-party certifying body programs (ISO/ICE 17060 & 17065.) Julie is known for her ability to develop and grow products, programs and teams, most notably the WELL AP credential, WELL Performance Verification and the WELL Performance Testing program and the Network Care team at IWBI.  

You can reach Julie at: jwojnowski@citadelehs.com

Mark Drollinger, M.Eng, CSP, CHMM, EiT

Principal, Engineering & Environmental Sciences

As Principal of Engineering and Environmental Sciences, Mark has a level of expertise and experience accomplished by few, with a strong knowledge of EPA, AQMD, OSHA, and DOT regulations. He brings 35 years of managing Environmental, Health, and Safety (EHS) projects to the team.

A key negotiator for local, state, and federal agencies, Mark is accustomed to coordinating a complex array of multi-disciplinary project teams, while also taking on various high-level responsibilities: developing and implementing health and safety protocols; overseeing all engineering and geological science projects; and coordinating with his project managers and staff to solve the sometimes typical, but often complex and specific needs of each client.

You can reach Mark at: mdrollinger@citadelehs.com.

Greg S. McIver

PRactice Leader, ENGINEERING & ENVIRONMENTAL SCIENCES

Mr. McIver is a Principal Scientist, Co-Practice Lead and is on the Board of Directors at Citadel EHS.  Mr. McIver has more than 25 years of experience in the environmental consulting field with a broad range of project experience including phase I/II site assessments, legal support, remedial pilot studies, remedial action design and implementation, vapor mitigation, bioremediation, cost to closure cost modeling, and risk sharing contracting structure.  His portfolio includes varies types of industrial facilities, property transaction and redevelopment support, former dry cleaner facilities, fuel and service stations, railroads, DOD tank farms, irrigated lands, mines, and SCAP grants.  The focus of Mr. McIver’s experience is successful site closure strategy execution and effective regulatory management.  Mr. McIver Co-Founded RMD Environmental Solutions in 2018, which sold to Citadel EHS in December of 2022.  Mr. McIver is an active member of the Nevada County Search and Rescue Team.

You can reach Greg at: gmciver@citadelehs.com

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