The Arkansas Supreme Court upheld recently the decision of a state trial court to bar a methodologically unsound expert report that sought to link fertilizer to a child's cancer. Green v. George's Farms Inc., No. 10-26 (Ark. 2/17/11).

Defendants/Appellees were engaged in the poultry-production business in northwest Arkansas. For decades, their feeds have included the additive 3-Nitro, an FDA-approved product that is used to promote growth and prevent disease. Feed turns into excrement. Growers typically remove the chicken litter from poultry houses once a year, and the litter is then applied as fertilizer -- in this case to the fields surrounding plaintiffs' home, including areas near several schools. The chicken litter is spread primarily in the spring and fall, commonly at a ratio of two tons per acre. Sounds like good recycling. But, said the court, roxarsone, an organic derivative of arsenic, comprises twenty percent of the ingredients contained in 3-Nitro. Arsenic, said the court, is a carcinogen and is considered both a cancer-causing agent and a promoter of cancer. The roxarsone that is fed to the chickens degrades into an inorganic form of arsenic that is excreted by the chickens.

Plaintiff Michael Green, was born and raised in the neighborhood near the schools and fields. In the fall of 1999, he experienced unexplained bruising, and was eventually diagnosed with a rare form of leukemia called chronic myelogenous leukemia (CML). He sued, alleging that the arsenic-laced litter produced by roxarsone-fed chickens polluted the air as a result of ventilating the chicken houses, and that dust clouds formed when the litter is spread, and that exposure to this inorganic arsenic caused his leukemia. (Other plaintiffs joined in the complaint, but the trial court severed the claims of the other plaintiffs.)

In pretrial rulings, the circuit court granted summary judgment in favor of defendants on the issue of causation. Additionally, the court excluded under the Daubert rule all testimony pertaining to certain parts of a report entitled “Exposures to Carcinogenic Arsenicals and Other Toxic Substances in Washington County, Arkansas,” prepared by plaintiffs’ expert, Dr. Rod O’Connor.

On the (first) appeal the supreme court held that a question of fact remained on the issue of causation. Green I, 373 Ark. at 396, 284 S.W.3d at 42–43. However, the court found no abuse of discretion in the circuit court’s decision to exclude the testimony. Id. at 408, 284 S.W.3d at 51. On remand, the trial court granted a directed verdict, and this, the second appeal, ensued.

Noting that the lack of publication and peer review had influenced the court’s earlier decision, appellants asserted that Dr. O’Connor’s work had since been peer reviewed and published, and thus it should have been admitted on remand. Defendants responded that the law-of-the-case doctrine precluded reconsideration of this issue. The trial court found that the published article utilized the same unreliable methodology to estimate peak air exposure concentration that it had previously ruled inadmissible. The trial court also stated that the expert's calculations were based on unreasonable assumptions and scientifically unsound mathematical extrapolations from dust samples collected in the area, and that Dr. O’Connor continued to use a formula that the EPA had warned should only be used to determine air levels of lead. The trial court found that the theory advanced by the expert had never been tested and still had not been sufficiently tested by any other scientist.

The doctrine of law of the case prohibits a court from reconsidering issues of law and fact that have already been decided in a case. The doctrine also provides that a decision of an appellate court establishes the law of the case for the trial upon remand and for the appellate court itself upon subsequent review. The law-of-the-case doctrine in some forms also prevents consideration of an argument that could have been raised at the first appeal and is not made until a subsequent appeal. The doctrine serves to effectuate efficiency and finality in the judicial process, and its purpose is to maintain consistency. The law-of-the-case doctrine is conclusive only where the facts on the second case/appeal are substantially the same as those involved in the prior appeal, and it does not apply if there was a material change in the facts.

And that was one of the issues here. The record reflected that the rejected parts of Dr. O’Connor’s report included his calculations relating to inhalation exposure reconstruction that were based on a formula for converting measurements of arsenic in dust to measurements of arsenic in air. Plaintiffs argued that publication and peer review of his methodology represented a material change in circumstances that would permit reconsideration of this issue. However, the court recognized that publication is not a talisman or "get out of jail free" card from our favorite old board game. It was not apparent to the court whether the specific inhalation exposure reconstruction reflected in the report was indeed subjected to peer review in the article. The fact of publication (or lack thereof) in a peer reviewed journal thus is a relevant, though not dispositive, consideration in assessing the scientific validity of a particular technique or methodology on which an opinion is premised.

Here, the absence of peer review and publication was but one factor in the overall assessment of the validity of Dr. O’Connor’s methodology. Given the serious flaws exposed in the expert's methods, the court was not persuaded that the publication of the article in a peer-reviewed journal constitutes a new fact that is sufficiently material to overcome the law-of- the-case doctrine. Further, plaintiffs’ argument that criticisms of his methods should only affect the weight but not the admissibility of the evidence was also barred by law of the case.