In the past, one of the most difficult aspects of bringing a lawsuit based on toxic chemical exposure has been proving a causal link between the exposure and cancer. Defendants in these cases often file countless motions challenging plaintiffs’ proof on the causation issue. With some regularity, defendants have succeeded in preventing certain cases from being decided by a jury. It has only been in cases involving rare malignancies, like mesothelioma, that establishing the necessary causal connection has been relatively straight-forward. That is because it has been proven that mesothelioma is caused only by exposure to asbestos.

When exposure a toxin causes a mutation that leads to a malignant change in a cell, and when that change eventually progresses to a tumor, there is no “eyewitness” to the event. In many instances, there are a number of possibilities besides the toxic exposure that defendants can claim caused or contributed to the mutation. One such possibility which often is difficult to discount is the possibility that a congenital defect, suggested by a family history of cancer, was a causative factor.

Unique mutations tied to specific exposures

With the mapping of the human genome, there is promising new research to help establish the causal connection between exposure to a toxin and the development of a particular malignancy. For instance, as a result of numerous epidemiological studies, kidney cancer has long been suspected to be caused by the common solvent and groundwater pollutant trichloroethylene (TCE).

In one study, German researchers examined a cohort of workers with heavy occupational TCE exposures who later developed kidney cancer. The researchers found a specific and unique gene mutation in the vast majority of the workers who developed kidney cancer. As further research occurs, more specific mutations matched to particular types of cancer and toxic chemical exposures are likely to surface. Worldwide databases are being developed to help accumulate this evidence. The effort is growing exponentially because of the free-sharing paradigm followed for the human genome project.

Ruling out inherited cancers

In addition, genetic analysis of cancer cells can provide other important clues which will be helpful in establishing causation. For instance, by comparing the genetic code of a cancerous tumor cell with the code of a non-cancerous cell, the possibility of a congenital defect can definitively be ruled out. Since all cells derive from the initial combination of the egg and sperm, all DNA strands in all cells should contain the exact same genetic code. Thus, a congenital gene mutation will be found in the DNA of both cancerous and non-cancerous cells from the same person. When the mutation only appears in the cancerous cell, it definitively rules out congenital mutations and suggests that some toxic chemical exposure likely played a role.

Moreover, the frequency of mutations in cancer cells also helps point to toxic exposure as a cause of a malignancy. The genes of populations exposed to known and suspected carcinogens tend to contain multiple defects analogous to what one expert has termed “carpet bombing” of the DNA strand. When this is found, it strongly suggests that the patient was exposed to a strong mutagen.

As research continues, the mystery and the difficulty of proving the causal link between a known toxic chemical exposure to a mutagen and the development of particular types of cancer should steadily dissolve. This will benefit the thousands if not millions of cancer victims who now cannot establish the requisite causal link to a toxic chemcial exposure and therefore are deprived of any compensation.

Written by: Stephen G. Schwarz, Managing Partner, Faraci Lange, LLP

In recent years, however, the danger of vapor intrusion is finally getting the attention it deserves from regulators and legislators across the country. One of the largest vapor intrusion sites discovered to date is in Endicott, New York. A plume of TCE and other VOCs are contaminating the air in hundreds of Endicott homes, requiring the installation of hundreds of individual vapor intrusion remediation systems. Faraci Lange, LLP, a Rochester, New York law firm, is involved in toxic chemical exposure litigation commenced against IBM on behalf of the victims of this contamination.

What is vapor intrusion?

TCE and other VOCs are by definition volatile. What this means is that when dissolved into or mixed with groundwater, they do not tend to stay put. Instead, they tend to revert to a gaseous phase and drift upward through the soil toward the surface. Whether a particular VOC plume in the groundwater will present a vapor intrusion problem is a function of a number of variables.

First and foremost, the concentrations found in the plume are important. Obviously, the higher the concentrations, the more unstable the plume and the more likely vapor intrusion will occur. Second is the depth of the plume. Groundwater plumes can be shallow, meaning that they are contained in what is termed the “overburden” groundwater, or they can be found in deeper, more permanent groundwater layers. The more shallow the plume, the less distance vapors volatizing out of the plume have to travel before getting to the surface. Therefore, more shallow plumes present a greater likelihood of intrusion. The nature of the soil above the groundwater plume is also an important factor. Soils that are relatively impervious to gas transport are less likely to permit volatized vapors a path to the surface. Conversely, sandy and coarse soils with multiple air spaces present ideal conditions for vapor intrusion.

Even when vapor intrusion is present in a particular neighborhood, the risks to the residents will not be uniform. Homes with deeper and more porous basements will allow more intrusion than those with more sealed foundations and slabs. Other factors, such as the time of year and the circulation inside the house, will play important roles.

What can be done to protect residents from vapor intrusion?

Because of their volatile nature, attempts to remove TCE and most VOCs from groundwater typically involve what are referred to as pump and treat remediation systems. Contaminated groundwater is pumped to the surface to air strippers which permit the volatilization of VOCs into a tower. From the tower, the VOCs are discharged into the atmosphere or captured in various charcoal type filters for disposal. However, this process is neither fast nor highly efficient. Over many years, this type of technology can reduce the concentrations found in a particular plume. Unfortunately, the presence of the contaminant can never be eliminated completely.

When vapor intrusion is discovered, individual remediation systems must be installed on a house by house basis. This process involves drilling into the foundation and installing a suction system that pulls vapors from beneath the subslab and vents them out above the roof of the house. In order to be effective, these systems need to run 24 hours per day, 7 days per week. They also require effective sealing of all points of entry into the home, including basement floor cracks and utility service entries, to prevent vapor intrusion.

Communities in which there had been confidence that a groundwater problem was harmless are being reinvestigated now by authorities who are looking for the insidious hazard of vapor intrusion. Given the thousands of known TCE plumes throughout the United States, it is extremely likely that vapor intrusion similar to that discovered in Endicott, New York is occurring in numerous other communities and causing potential future illness to thousands.

Written by: Stephen G. Schwarz, Managing Partner, Faraci Lange, LLP