Principal Toxicologist​/Health Scientist​/Risk Assessor

Job Details

• Job Location: Houston, TX - Houston, TX 77098
• Position Type: Full Time
• Education Level: Graduate Degree
• Job Category: Science

GSI is a privately held, employee‑owned company offering superior compensation, benefits, professional development, with 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 its 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 with seamless collaboration over both technical 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 of environmental professionals perform projects nationwide and internationally. Key opportunities of the Principal role will include:

• 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.

We are seeking a highly experienced and strategic Principal Toxicologist/ Health Scientist/ Risk Assessor to join our growing team. This leadership role will drive technical excellence, mentor associate staff, and lead multidisciplinary teams involving toxicology, health sciences and/or environmental risk assessment in support of site investigations, remediation, regulatory compliance, and litigation matters.

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

• Lead and manage complex human health and ecological risk assessments for contaminants in soil, water, air, sediment, and consumer products.
• Interpret and apply federal and state risk assessment guidance (e.g., USEPA, CalEPA, regional agencies).
• Provide technical oversight and quality assurance on deliverables.
• Develop exposure scenarios for a wide range of receptors and pathways.
• Provide litigation support services on matters involving conceptual site models and exposure pathways, toxicology, risk assessment, and general causation.
• Communicate risk assessment findings to clients, regulators, and stakeholders through reports, presentations, and public meetings.
• Support business development efforts by identifying new opportunities, preparing proposals, and cultivating client relationships.
• Mentor and train associate and mid‑level staff in risk assessment methodologies, toxicology, 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.
• Minimum of 15 years of professional experience in toxicological sciences and human health risk assessment, with at least 5 years in a leadership or project management role.
• DABT Professional certification or others (e.g., CIH, etc.).
• Demonstrated expertise with federal and state risk assessment guidance and regulatory frameworks (e.g., CERCLA, RCRA, TSCA, DTSC, CalEPA, OEHHA).
• Experienced in effective risk communication to clients, regulators and public stakeholders through reports, presentations, public communication postings, and meetings.
• Proven ability to manage multiple projects, lead cross‑discipline technical teams, and interface with clients…