Principal PFAS Toxicologist

Position Overview

GSI Environmental Inc. (GSI) seeks a highly experienced Principal PFAS Toxicologist to join our growing team. This leadership role will drive technical excellence, mentor associate staff, and lead multidisciplinary teams involving toxicology, health sciences, and environmental risk assessment in support of regulatory compliance and litigation matters. The right candidate will enjoy a generous compensation and benefits package, a substantial performance-based bonus, meaningful ownership in a growing, highly profitable, privately-owned firm, the ability to participate in firm leadership, and the freedom to develop a practice within a supportive and collaborative environment.

We are a privately held, employee‑owned company offering superior compensation, benefits, professional development, and ownership opportunities for excellent candidates. GSI is highly respected nationally and internationally for the quality of its professional environmental services and the technically advanced projects it has completed over 39 years of operation. GSI employs cross‑disciplinary teams of environmental engineers and scientists, including toxicologists, geologists, hydro geologists, ecologists, chemists, oceanographers, and data scientists who collaborate seamlessly across disciplines and offices.

Headquartered in Houston, Texas, GSI operates offices in Texas (Austin and Houston), California (Irvine, the San Francisco Bay Area, and Folsom), Washington (Olympia), Montana (Missoula and Helena), North Carolina (Raleigh), and New York (Syracuse). Our talented staff perform projects nationwide and internationally.

Near one of our existing office locations. Remote arrangements will be considered for exceptionally qualified candidates.

• Join a Thriving Firm:
  Be part of a privately‑owned company renowned for its technical excellence and strong industry reputation. We are committed to measured, purposeful growth that maintains the integrity of our unique culture.
• Be a Leader and Owner:
  Take on a significant role in managing a mid‑sized company with over 250 employees. Enjoy meaningful ownership and profit‑sharing opportunities that recognize and reward your contributions.
• Advance the Science:
  Lead and innovate in the fields of toxicology, health sciences, and risk assessment. Your expertise will drive advancements and make a tangible impact on our projects and the industry.

• Provide litigation support services on matters involving PFAS toxicology, risk assessment, and general causation. Develop and interpret conceptual site models and identify exposure pathways.
• Lead and manage complex human health and ecological risk assessments for PFAS in soil, water, air, sediment, food, and consumer products. Follow the emerging science and regulation of PFAS in biosolids, and understand how these developments may affect clients and present business opportunities.
• Communicate risk assessment findings to clients, regulators, and stakeholders through reports, presentations, and public meetings.
• Interpret and apply federal and state PFAS toxicology and risk assessment guidance (e.g., USEPA, CalEPA, state agencies).
• Follow PFAS toxicology and exposure guidance developments from European and Australian agencies such as EFSA, and understand how this guidance may affect US clients.
• Support business development efforts by identifying new opportunities, preparing proposals, presenting webinars and similar presentations to professional and scientific organizations, business groups, and others; and use these venues to cultivate client relationships.
• Provide technical oversight and quality assurance on deliverables.
• Mentor and train associate and mid‑level staff in toxicology, risk assessment methodologies, regulatory frameworks, and scientific best practices.
• Collaborate with technical staff across disciplines and offices.

• Advanced degree in Toxicology, Public Health, Environmental Science, or related field;
  PhD preferred.
• Minimum of 15 years of professional experience in toxicological sciences and human health risk assessment, with at least 5 years in a…