Example Activities

            For a major pesticide manufacturing company, Sielken & Associates conducted a pioneering probabilistic aggregate risk assessment that included exposures from residential, drinking water, and dietary pathways. Dr. Robert Sielken and other members of Sielken & Associates staff calculated population exposures for these combined pathways and avoided adding together the worst-case exposures from each individual pathway.

            Dr. Sielken provided affidavits, submissions to the California Department of Health Services, expert testimony, and other litigation support for a law firm in the areas of exposure assessment and quantitative risk assessment for a Proposition 65-listed chemical, DBCP (1,2-dibromo-3-chloropropane) in drinking water. Flaws in the plaintiff's exposure assessments and risk characterizations were identified, and Sielken & Associates developed alternative, science-based analyses, indicating de minimis exposures and risks. Sielken & Associates also developed comparisons with other common risks. Several related cases over a 10-year period were decided in favor of the defendant companies, demonstrating the importance of applying the best available science.

            For numerous clients, Sielken & Associates has developed probabilistic quantitative risk assessments for a variety of environmental exposures and risks. For example, following a fire at a large dry cleaning facility, Sielken & Associates facilitated a town meeting to help community members place in proper perspective the risks associated with this accident. Also, at a Superfund site, by communicating complex risk assessment issues to diverse audiences, Sielken & Associates worked with legal support to foster negotiations between community leaders, potentially responsible party (PRPs), regional EPA, and state health officials.

            For a major chemical trade association, Sielken & Associates is helping to prepare more realistic exposure assessments of consumer and industrial uses of chemicals in conjunction with product stewardship initiatives.

            To assist in the updating and enhancement of regulatory databases (e.g., IRIS), Sielken & Associates is helping to develop extramural risk assessments for submission to EPA. Such submissions could result in the reclassification of the carcinogenicity of a chemical, a reexamination of the potency, and/or a less stringent reference dose.

            For a major industry trade association, Sielken & Associates has developed dose-response and risk management tools for working environments involving fumes containing multiple components that interfere with each other's biological activity.

            For a consortium of pesticide manufacturers, Sielken & Associates is developing better methods for use by the regulatory agencies preparing aggregate and cumulative risk assessments under the Food Quality Protection Act.

            For many clients, Sielken & Associates is identifying and resolving problems with major impacts hidden in large complex analyses.