Hydrologist’s Expert Testimony Allowed in Groundwater Contamination Case

Defendant is accused of contaminating groundwater near a missile motor casings site. Plaintiff challenged the expert witness testimony of defendant’s hydrologist expert.  The court denied the motion to exclude.

Facts: This case (Alexander et al v. Halliburton Company et al – United States District Court – Western District of Oklahoma – May 16th, 2016) involves the alleged contamination of groundwater near a missile motor casings site.  The plaintiff’s allege that as a result of the activities at the site, the groundwater became contaminated with perchlorate, which has since moved to the private wells of nearby residents.  The plaintiffs’ hired Dr. Richard Laton and Dr. Robert C. Knox as experts and the defendants hired Steven Larson (Hydrology & Groundwater Expert Witnesses), who supplied a critique of these experts.  The plaintiffs filed a motion to exclude certain parts of Mr. Larson’s testimony.

Discussion: Specifically, the plaintiffs’ seek to exclude the following opinions: 1) Opinions on future remedial actions; 2) opinions regarding the flow direction and velocity of the affected groundwater; 3) opinions on the groundwater contamination at concentration levels less than 11 ppb; 4) opinions on the background levels of perchlorate; and 5) opinion on the reliability of the “Shipman Sample”.

The court looked at each challenged opinion separately and concluded that the motion should be denied in all aspects.

First, the plaintiffs argue that Mr. Larson will provide testimony as to future remedial actions that Halliburton may take, directed by the Oklahoma Department of Environmental Quality (ODEQ), which they say is speculative.  The defendants argue that they have already entered into a Consent Order with the ODEQ and has approved three remedial measures to prevent future migration of perchlorate.  The court agreed, stating that this part of the testimony is not speculative and should be allowed.

The plaintiffs next contend that Mr. Larson’s testimony on the flow direction and velocity of groundwater should not be allowed as his opinions are not supported by reliable scientific data or methodology.  The court disagreed, stating that these opinions are based on sufficient scientific data and that these arguments go to the weight of the testimony, not the admissibility. In addition, the court also struck down the argument that Mr. Larson’s opinion on the location of the perchlorate in the water at less than 15ppb.  The plaintiffs maintained that Mr. Larson’s report did not include an opinion or analysis of the location of the perchlorate in the water at less than 15ppb.  The court opined that this argument goes to the weight of the testimony, not the admissibility.

The penultimate issue is Mr. Larson’s opinion on background levels of perchlorate.  The plaintiffs argue that his opinions are based on a method that is not accepted in the scientific community, and hasn’t been published in a peer-reviewed scientific journal.  Mr. Larson stated that his methods were published in a paper in 2014 and was was reviewed and approved by the EPA.  The court again decided that this opinion will be allowed.

Last, the plaintiffs argue that Mr. Larson’s opinion on the “Shipman sample” (a sample of well water that was taken from a nearby residential location in 1988) is unreliable as he is not qualified as an analytical chemist.  The court again disagreed, stating that his is qualified to offer an opinion on the “Shipman sample”

Conclusion: The motion to exclude the expert witness testimony of Steven Larson was denied.