Dr. Thomas has provided expert witness testimony concerning health effect
claims following a derailment of a tank car, spilling a high-aromatic naphtha
in a river emptying into Lake Superior. The geographic pattern and maximum concentrations
for specific volatile constituents along the river were used to evaluate whether
symptoms and conditions of people claiming exposure are consistent with what
is known about the spilled hydrocarbons.
He has also been an expert witness in several cases concerning the relationship of benzene with various hematological conditions and malignant cancers, and has been involved in several cases alleging neurotoxicity, reproductive toxicity, birth defects, or cancer due to occupational exposure to solvents, petroleum hydrocarbons, industrial chemicals, pesticides, and diesel exhaust.
Dr. Thomas has been designated expert in several suits (involving 15,000
plaintiffs) that resulted from the rupture of four pipelines (natural gas, unleaded
gasoline, diesel fuel, and crude oil) during the record 1994 flood of the San
Jacinto River. Depending on the time of day and location, a plaintiff's exposure
may have been exposed to a constantly changing mixture of light-end petroleum
hydrocarbons that volatilized from the oil slick as it moved down the river,
and/or combustion products formed by the subsequent river fire. Municipal and
medical wastes from upstream sources also complicate the analyses in these cases.
· Testifying expert in a case of a man claiming a wide variety of health problems which he believed were associated with his exposure to asphalt fumes from his work. He was employed as a driver of a spray truck for repaving roads using an asphalt that was cut-back with kerosene. During the trial, the Plaintiff played a videotape of a repaving operation showing a billowing white cloud behind the spray truck. In my testimony, a short description of petroleum refining process gave the jury an understanding that kerosene begins to distill at a temperature of about 400ºF and that asphalt will not generate a fume until heated to temperatures greater than about 650ºF and more likely >1000ºF. Because the operating temperature of the spray truck was only 250ºF, the Plaintiff did not have significant exposures to either asphalt fume (which is dark not white) or to kerosene vapor. The white cloud seen in the videotape was steam formed when the hot asphalt spray (250ºF) contacted water (boiling point = 212ºF) in the cracks of the road being resurfaced. Alternative causes for the Plaintiff's health complaints were suggested based on his medical records. The jury found for the Defendant within 45 minutes.
· Testifying expert in case alleging severe restriction of lung expansion caused by pulmonary scarring (fibrosis) as a result of Plaintiff's workplace inhalation of aluminum welding fume. Scar tissue (when present in the lungs to a significant degree) cannot stretch, and restricts the lungs from expanding fully. Opposing experts in the case stated that the Plaintiff had the highest concentrations of particles in the lung that they had ever seen, and that the majority of these particles were physically and chemically consistent with aluminum welding fume. A biopsy of lung tissue was described as having a "burnished" appearance. After reviewing the medical records and published literature, it was demonstrated that the Plaintiff's pulmonary problems were primarily obstructive lung disease due to his long history of cigarette smoking, and that the Plaintiff's development of a "barrel chest" (hyper-expansion of the lungs secondary to emphysema) confirms that aluminum welding fume (like iron welding fume) does not cause pulmonary scar formation to an extent that results in restrictive lung disease.
· Consulting and/or testifying expert in several cases alleging various adverse health effects due to exposure to various metals and mineral dusts. Plaintiffs included railroad workers (taconite dust) welders/foundry workers (fumes from molten steel), and residents in a community located downwind from a commercial facility that recycled automotive batteries (lead).
· Testifying expert in several cases alleging hematological cancers and related disorders associated with workplace exposures to benzene. After reviewing the medical records in these cases, it became apparent that the Plaintiff's either did not have a type of cancer associated with benzene, or did not have a preceding history of severe benzene intoxication that is necessary for the development of Acute Myelogenous Leukemia (the type of cancer associated with benzene).
· Testifying expert in a case involving seven men who were killed in an explosion during a snubbing operation at a natural gas well. Based upon a review of autopsy records and other documents, it was clear that the men were killed outright by the pressure wave of the explosion. All of the victims suffered extensive third and fourth degree burns on their bodies (postmortem). However, there was no increase in the carboxyhemoglobin concentration in the blood and no evidence of soot or thermal injury in the lower respiratory tract, indicating that they had ceased breathing before being burned and therefore did not experience pain and suffering. One individual (a non-smoker) showed elevated carboxyhemoglobin levels, but no evidence of soot or thermal injury in the trachea; this was because the victim had been eviscerated by the shock wave created by the blast, allowing carbon monoxide to diffuse through the exposed peritoneal membrane and to bind to hemoglobin (postmortem).
· Consulting expert in a case involving the exacerbation of porphyria in a teacher exposed to an organophosphate insecticide that had been sprayed in her classroom by maintenance personnel. The issue in this case was whether her treating physicians should have recognized her symptoms and initiated treatment before her disease became debilitating. It was shown that the organophosphate used can inhibit a specific porphyrin-metabolizing enzyme that results in the form of porphyria she developed.
· Testifying expert in a case heard in the High Court of New Zealand involving a farmer who sued the New Zealand Air Force for contaminating his groundwater and causing the illness and death of livestock and wild animals on his property, as well as numerous health effects in his family. The primary toxic agent suggested as being responsible was a neurotoxic additive in jet turbine oil that was burned in open pits at the base. However, that chemical is poorly soluble in water, adsorbs tightly to soil particles, and is therefore unlikely to have migrated over 3,000 meters to the farmer's property. In addition, the particular symptoms and necropsy findings seen in the animals were consistent with common veterinary diseases seen in New Zealand, especially in the unusually wet conditions that were extant at the time. Specifically the neurological and other findings were more likely explained by the animals' ingestion of mold and associated mycotoxins. Based on the presented evidence, the Court ruled in favor of the Air Force.
· Testifying expert in a case involving a short-duration release of sulfur dioxide into the air during a process upset at a refinery in Texas City. Sulfur dioxide (SO2) dissolves in water to form sulfurous acid. Approximately, 4400 residents filed suit alleging that the suffered skin and eye irritation, as well as respiratory symptoms and other effects because of their exposures to the plume of SO2. Case is ongoing, but available meteorological data indicated that the plume most likely traveled across only a small corner of the city and out to the Gulf of Mexico, and that most of the plaintiffs in this case were not at locations where they could have been exposed to SO2 (all but c. 125 plaintiffs have been dismissed from this case). While some of the alleged symptoms are consistent with those associated with acute SO2 exposure, they occur in a time sequence and combinations that are inconsistent with the facts of this release, and it is telling that none of the plaintiffs in this case sought medical attention in the days following the incident.
· Testifying expert in a case involving long-term water damage to a church in Texas, leading to blossoming of "toxic mold", and claims that the church facilities are unusable in their present condition. The church is suing their insurance carrier for the costs of demolishing and rebuilding the buildings. Based on my statistical analysis of bioaerosol data collected by another consultant, it became clear that, as expected, conditions inside the Church buildings favor the growth of different types of fungi (primarily Penicillium and Cladosporium) than those that grow outdoors (primarily Basidiomycetes). However, the measured levels of these fungal bioaerosols were seen to differ from expected indoor concentrations (i.e., fungal contamination) was seen in only six rooms. Species of "toxic mold" (e.g., Stachybotrys chartarum, Chaeetomium spp.) were seen at low levels in only a few of the collected samples. Complete destruction of the buildings, from a health point-of-view, is excessive and unwarranted.
· Testifying expert in a case involving a painter/sandblaster who developed progressive, debilitating lung dysfunction (diagnosed as silicosis because of his work history, but overlying COPD associated with smoking). This diagnosis led him to sue his previous employers. Upon his death, his attorney hired a pathologist to conduct an autopsy. The pathologist reported finding needle-shaped crystals consistent with silica and concluded that the gross and microscopic changes seen were consistent with silicosis, which he listed as the cause of death. The pathologist was apparently not aware that this man had pulmonary tuberculosis as a young man, and had at least two recurrences of his TB documented in the medical records. It was surprising therefore, that no tissue evidence of chronic tuberculosis was mentioned in the autopsy report. In addition, the sand used for blasting purposes comprises spherical particles that fracture when impacted at high velocity against a hard surface, forming small, sharp-edged chips that are capable of injuring the delicate tissues of the lung (i.e., producing the changes of silicosis). It is not clear what the needle-shaped crystals seen by the pathologist are, but they are not found in sandblasting, and the patient most likely died of a pulmonary infection secondary and chronic lung injuries sustained as a result of repeated infections by tuberculosis and as a result of his long smoking history. The case is ongoing.
· Consultant to a major U.S. pipeline company concerning the risks to their operations from possible chemical/biological/radiological attack following the events of 9-11 and the subsequent anthrax scare. Addressed issues ranging from intentional adulteration of transported products which would then be sold to and used by the general public, to potential attacks on operation centers and personnel in order to disrupt energy flow in the United States.
· Testifying expert in several cases concerning the evolving understanding of the adverse health effects associated with various forms of asbestos (i.e., the state of the knowledge) and the level of understanding that would have been expected of a small insulation installer.
· Consultant to a school district in Texas concerning the possibility that adverse health complaints reported by students and staff at one school might be related to exposures to environmental contaminants within and outside the building. The list of potential toxic agents evaluated included metals, volatile compounds (e.g., solvents), and semi-volatile compounds (e.g., pesticides).
· Consultant to a fish meal/fish oil manufacturer who identified high levels of polycyclic aromatic hydrocarbons (PAHs) in the surface soils at a facility they had leased. The initial review of the analytical data conducted by Dr. Thomas suggested (because of the concentrations and sizes of the observed PAHs) that the contamination was not the result of spills of petroleum products, but more likely were associated with coal-derived bitumen. Subsequent examination of soils at the Site confirmed the presence of small tar-like particles in the surface soil samples, and that a previous lessee of the property was a scrap company that dismantled offshore oil platforms. The surfaces of such platforms are often coated with coal-tar enamel. The available toxicological literature shows that PAHs that are entrained within particles of tar are not available to contact biological tissues and do not pose a risk to health. Clearly in this case, there was a logical disconnect between the elevated concentrations of PAH (leading to highly stringent risk-based cleanup criteria) and the apparent health risks at this Site. Dr. Thomas suggested that the high levels of PAHs seen in this case are an artifact of the standard analytical methods for determining PAHs, which use methylene chloride as the extraction solvent. Methylene chloride dissolves tar and asphalt, freeing the PAHs for chemical analysis. He therefore designed an alternative analytical procedure using n-pentane as the extraction solvent (the old name for asphalt was "pentane insolubles"), and used the modified procedure to demonstrate that the soil PAHs at this site are almost entirely entrained within the tar particles and are not extractable by n-pentane. These data also explained why previous attempts to biotreat the soils at this site failed - the PAHs in the tar particles are not accessible by n-pentane nor by the biological solvent system (e.g., fatty acids and phytosterols) of soil microbes.
A detailed list of Active and Settled Cases is available upon request from
identified, appropriate individuals.
Dr. Thomas also presents regular lectures at the Institute of Environmental Technology on toxicology, risk assessment and associated litigation issues.
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Last Update: July 7, 2003