PFAS exposure assessment in class action litigation

Per- and polyfluoroalkyl substances (PFAS) detected in groundwater and several municipal drinking water plants in southeastern Ohio, USA, have been linked to emissions from a major PFAS facility in West Virginia.

A class action suit filed in Ohio alleges that a range of health effects experienced by individuals in the community has been caused by PFAS in the drinking water supplied by the municipal plants and groundwater. Damage claims in the suit total well over $100 million.

In 2021 Ramboll was asked to prepare separate expert reports for over 25 individual plaintiffs and presented expert testimony at deposition. For each plaintiff, Ramboll developed an exposure profile detailing potential levels of exposure to PFAS in groundwater and air at home, school and work, over periods of up to 30 years.

Exposures were put into the context of evolving historical PFAS regulatory criteria, and the results of both occupational and public health surveys and epidemiological studies.

Ramboll conducted detailed reviews of individual plaintiff depositions and surveys to recreate drinking water histories, and then compiled data on measured or estimated PFAS concentrations in the drinking water over time. The potential for exposure to PFAS in air was also evaluated.

Based on this analysis, Ramboll developed quantitative estimates of PFAS exposure for individual plaintiffs, for comparison against heath-based criteria, regulatory standards and the results of health surveys. Ramboll then provided expert testimony regarding the extent to which individual plaintiffs may have experienced PFAS exposures in excess of these benchmarks.

Ramboll’s assessment and testimony was instrumental in helping to differentiate between plaintiffs whose PFAS exposures may have been above levels of concern, and those whose exposures were demonstrably lower than such levels.