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Ms. Zemo is an experienced expert witness and confidential litigation consultant. She has been deposed, prepared declarations and expert opinion reports, and has testified in binding arbitration hearings, jury trial and bench trial.  A complete listing of Ms. Zemo’s expert witness testimony is available upon request. Representative cases/assignments include:

Expert Witness for Defendant, Diesel/Bunker Fuel Remediation, Former Railyard.  Ms. Zemo was an expert in the case City Parkway v. UPRR (U.S. District Court, District of Nevada) in which she rendered written opinions and deposition testimony regarding whether defendant had met regulatory requirements for investigation and remediation even though “TPH” was found in shallow soil during property redevelopment after remediation was complete.  Her opinions addressed areas including regulatory compliance, the uncertain nature of the “TPH”, and health-protective cleanup concentrations.

Expert Witness for Plaintiff, Age-Dating of Diesel Release. Ms. Zemo was an expert in the case Blech v. Oceano Packing (case was arbitrated) in which she rendered written opinions, deposition testimony and hearing testimony regarding the age-dating of a diesel release to surface soil.

Confidential Consultant for Defendant, Dry Cleaner Litigation. Ms. Zemo is retained as a confidential consultant to a dry cleaner equipment manufacturer on a portfolio of several sites.  Services include assessment of: the fate and transport of PCE, release sources, and cost estimates for site remediation.  

Expert Witness for Joint Defendants, Diesel Release.  Ms. Zemo was an expert in the case Stockton Redevelopment Agency vs. BNSF and UPRR (U.S. District Court, Eastern District of California) in which she rendered written opinions and deposition testimony regarding the age-dating of the diesel release, the source of diesel and other chemicals found in site soil, and the appropriateness of the remedial actions performed by plaintiff.  Ms. Zemo testified at the bench trial.  

Fact Witness and Non-Retained Expert for Defendant, and Testimony at Jury Trial, Chlorinated Solvent Plume.  Ms. Zemo testified in the case Clark vs. UPRR, et al (Sonoma County Superior Court) regarding her previous work characterizing a chlorinated solvent plume that plaintiffs alleged had migrated to their properties. She explained to the jury about the techniques used in her work, her evidence that the data were representative, and that the plume had not migrated as alleged.  Her testimony was essential to the jury’s finding for the defense.  

Expert Witness for Defendant, Marine Sediments Offshore of Creosote Facility.  Ms. Zemo was an expert in the case Pacific Sound Resources v. Burlington Northern Santa Fe Railway Corporation (U.S. District Court, Western District of Washington) in which she rendered written opinions and deposition testimony regarding her forensic evaluation of the sources (petrogenic v. pyrogenic, and “urban background” v. site specific) of PAHs in sediments of Elliot Bay, Seattle, Washington.  

Confidential Consultant for Joint Defense Group, MTBE Litigation.  Ms. Zemo was retained as part of a confidential consultant team for a large case focused on MTBE releases in the Central Valley of California.  Ms. Zemo provided input regarding the timing, magnitude and migration of releases from multiple facilities, and the efficacy of remedial actions at each facility.  

Confidential Consultant for Defendant, Mixed Releases: MGP Tar, Heavy Fuel Oils and Diesel.  Ms. Zemo was engaged to distinguish among impacts caused by MGP tars and heavy fuel oils that migrated downgradient into a separate diesel plume.  It was alleged that these fuels and tars had also impacted near-shore sediments.  Forensic interpretations of soil and sediments were primarily centered on previously-existing “TPH” and PAH data, and included evaluating chromatograms and constituent ratios.  The evaluation was successful in distinguishing the sources and costs were allocated accordingly.  

Expert Witness for Defendant, Dry Cleaner Litigation.  Ms. Zemo was retained as an expert in the case Adobe Lumber v. Taecker et al (U.S. District Court, Eastern District of California) in which she provided written opinions and deposition testimony regarding PCE impacts to soil and groundwater, and remediation cost estimates.   

Expert Witness for Cross-Defendant, Co-Mingled Dry Cleaner and Gasoline Station Plumes.   Ms. Zemo served as a technical expert in the case Clark v. Boyett et al (Sonoma County Superior Court) for a property owner impacted by both a PCE plume emanating from a dry cleaner and a BTEX plume from a former service station.  Ms. Zemo provided remedial alternatives and cost estimates for her client’s property and assisted during mediation among all the parties so that a comprehensive remedial strategy was selected. 

Expert Witness for Defendant, Solvent Storage Terminal Litigation.  Ms. Zemo was retained as an expert in the case Richmond Redevelopment Agency v. Petromark, Inc, et al (U.S. District Court, Northern District of California) in which she was to render opinions regarding impacts of PCE, TCE, and other chlorinated solvents to soil and groundwater and the appropriateness of remedial alternatives and cost estimates put forward by the plaintiff.  The case settled one day before submittal of expert reports.  

Expert Witness for Joint Defense Group, State-Wide Proposition 65 Litigation. Ms. Zemo was retained by a joint defense group of eight oil companies in the case Communities for a Better Environment v. Tosco Corp., et al. (San Francisco County Superior Court). This case centered on the timing of gasoline releases to the subsurface at hundreds of service station sites within California. She submitted to the Court a technical declaration that explained the common factors that influence analytical results and product thickness at fuel release sites, and the challenge of distinguishing between a new release and site-specific variability caused by non-release factors. In opposition to plaintiff’s expert, Ms. Zemo’s declaration included site-specific opinions about timing of release and factors causing concentration changes in monitoring data.  

Confidential Consultant for District Attorney.  Ms. Zemo provided confidential consulting to the Santa Clara County (CA) DA’s Office Environmental Enforcement Group in the prosecution of a case focused on the timing of releases from a retail service station and the delay in remediating an MTBE plume and source area.   

Confidential Consultant for Defendants, Port and Other Redevelopment Properties.  Ms. Zemo has been engaged on several matters for industrial clients in which Port authorities or other local government entities have claimed damages for remedial costs associated with property redevelopment under either the Polanco Act or other laws.  Her services have focused on environmental forensics (either product/material identification and attribution, or timing of the release) and/or appropriateness of the remedial action contemplated or undertaken by the Port or redevelopment agencies.  Constituents include petroleum, lead, tars, and chlorinated solvents.    

Member of Neutral Consultant Team. Ms. Zemo was part of a neutral consultant team engaged by counsel for four parties (three major oil companies and a county department) to collect and evaluate data from four adjacent former bulk fuel storage facilities for developing remedial cost allocations among the parties. The project included performing a CPT/LIF investigation for further source delineation (residual NAPL) and developing a 3-D visualization model to display all site data. Ms. Zemo evaluated the correlation between the new CPT/LIF results and historical soil TPH data in defining source areas.  Ms. Zemo was subsequently engaged as the neutral technical assistant to the mediator during cost allocation deliberations.
Expert Witness for Defendant, Product Identification Based on “TPH”.  This case focused on TPH data that plaintiff claimed proved hydraulic oil contamination to plaintiff’s soil and creek water.  After reviewing the chromatograms and other lab data, Ms. Zemo concluded that the “TPH” detections resulted from organic interferences to the measurement, and that no petroleum was present in the samples.  She collected site-specific samples of organic material (twigs, pine needles, leaves) that produced a fingerprint that matched plaintiff’s samples.  
Specialty Technical Consulting for Settlement Discussions. This assignment centered on the timing and migration of multiple fuel releases at an operating bulk storage terminal that changed ownership. Ms. Zemo argued to USEPA Region 9’s in-house counsel and project officers that the previous owner should be added to the site cleanup order because they were responsible for fuel releases prior to the property transfer date. Ms. Zemo presented the forensic chemistry basis for age-dating the gasoline, which relied on comparing ratios of key constituents that reflected changes in local refining practices over specific time periods. 

Expert Witness and Testimony at a Jury Trial. Ms. Zemo served as a testifying expert on the case Wine World v. The Beverage Source, et al (Sonoma County Superior Court). Her opinions focused on the development and discovery of a “smear zone” in the site subsurface subsequent to a fuel oil release, and using site physical and hydrogeologic data to estimate when the release occurred. Ms. Zemo also provided an opinion about the appropriateness of the remediation completed by the site owner. Ms. Zemo was deposed and later testified at the jury trial.   

Expert Witness for Arbitration of Service Station Portfolios. This case centered on the transfer of 200 retail service station properties between two major oil companies and allocation of environmental cost liabilities at each property. Ms. Zemo developed expert opinions regarding the source and timing of releases, site-specific vs. regional sources of MTBE in groundwater, interpretation of analytical data (including interferences to “TPH” and MTBE quantification), and appropriateness/efficacy of remedial solutions. Ms. Zemo submitted expert technical opinion reports for six sites. In addition to opinions on the source/timing of the release(s), each report contained a recommended cost allocation between the two parties. She provided expert testimony to a panel of three arbiters, including direct and cross-examination, at two arbitration hearings.  

Other Expert Witness and Confidential Consulting Assignments. Ms. Zemo has been engaged on several other matters either to render expert opinions or to provide confidential technical support centered on the issues of the interpretation of analytical data (in particular, detailed evaluations of “TPH” data), forensic chemistry of product composition, timing and magnitude of releases, site-specific vs. background sources of chemicals, fate and transport of groundwater plumes, and appropriateness/efficacy of remedial solutions.  These have included sites affected by petroleum hydrocarbons (crude oil, refined products, and residuals), oxygenates (MTBE, TBA, etc.), tars, chlorinated solvents, and PAHs.  Sites have been in California, Texas, Louisiana, Washington, Oregon, Wyoming, South Dakota, Utah, Idaho, Canada, and Ecuador.