The ruling against Chevron in the Ecuadorian court is based heavily on data from a series of judicial inspections of Chevron's former oil installations and waste pits, conducted from 2004 to 2007. The evidence that came out of these inspections was a major blow to Chevron, documenting extensive contamination well above legal limits at nearly every site. The $27 billion damages assessment released in 2008 by a court-appointed independent expert confirms this underlying truth.
Chevron has nonetheless tried to minimize evidence of its contamination using deceptive science. Experts for the plaintiffs observed during the inspection process that Chevron's sampling methods revealed an underlying and deliberate strategy aimed at avoiding results that could reflect poorly on the company. Their tactics included the following:
- During the inspections, the company's sampling experts frequently tried to lift soil and water samples from particular locations where they believed there was little or no contamination, even though the general area was extensively contaminated. For example, Chevron experts would often choose a soil sample from the surface of a dirt-covered pit, when most of the contamination was a few feet underneath. Or, the company might take a water sample from the top of a hill near the pit rather than below the gradient.
- Samples have been taken far from the natural gradient of the land to avoid toxic plumes that exist underground.
- To measure contamination in soil samples, Chevron's scientists made heavy use of a test called the Toxic Characteristic Leaching Procedure (TCLP) in which water is run through soil, and the concentrations of contaminants in the water are then measured. The TCLP test does not indicate the amount of contamination actually present in the soil sample. It is akin to running water through coffee grounds in a filter, then measuring the amount of caffeine in the water and trying to claim that it accurately represents the concentration in the coffee itself. While the TCLP test might indicate how much contamination would be released from a site in a single heavy rainstorm, it dramatically underestimates cumulative environmental damage over many years. For this reason, environmental regulatory authorities including the U.S. EPA consider TCLP an inappropriate test for the circumstance in which Chevron has applied it in Ecuador.
- Chevron also practices deception by using composite sampling, in which many soil samples are mixed together for testing and an average level of contamination is determined, rather than testing each sample individually. While composite sampling is appropriate in a situation in which pollution is fairly evenly dispersed, such as pollution from airborne particulates, it is NOT appropriate in a situation like that in Ecuador, where toxic waste is heavily concentrated at specific points. The U.S. EPA clearly stipulates that composite sampling is unacceptable where there are pollution "hot spots." Chevron's only defense of its use of compositing is that it is "authorized by Ecuadorian regulation" and was used by the company in its initial flawed remediation in the 1990s. This defense does not address the fact that in choosing to use a method that likely underestimates the extent of contamination, Chevron practices unsound and deceptive science.