The Court of Appeal has dismissed appeals by Brendan McGee and GMS Insulations Limited against the outcome of two personal injury claims brought by Patrick Duffy and Anita Duffy.
In a judgment delivered on 7 November 2022, Maurice Collins J agreed with Noonan J that the appeals should be dismissed, both on liability and on the amount of damages. Binchy J also agreed. The judgment discussed here gives Collins J’s additional observations about expert evidence; it does not set out the damages amounts or the full reasons on liability.
The claims arose from insulation installation work. The plaintiffs alleged they had been negligently exposed to isocyanate. The source does not specify where the installation took place. McGee’s defence called Dr Thompson, a toxicologist, as an expert witness. Collins J said the trial judge was entitled to reject his evidence.
The appeal judgment describes problems with Dr Thompson’s report and testimony. Among them, he expressed views on legal and medical issues outside his stated expertise, made categorical claims about disputed facts he had no independent knowledge of, and repeatedly accused the plaintiffs of dishonesty. Collins J also said Dr Thompson discounted documents put to him in cross-examination that were inconsistent with his view that exposure was scientifically impossible after 30 minutes.
The court concluded that Dr Thompson had shown he was unable or unwilling to comply with the duties of an expert witness. It held his evidence inadmissible and said it had to be disregarded in its entirety, rather than merely given less weight. The court was addressing the trial judge’s treatment of the evidence as part of the appeal, not conducting a separate trial of the plaintiffs’ allegations.
Collins J used the case to discuss expert evidence more broadly. He said Irish courts do not apply a general, specified reliability threshold as a condition for admitting expert evidence, but reliability can be challenged and can affect admissibility or weight. He also said a significant failure of objectivity, impartiality or independence may make expert evidence inadmissible.
The judgment stressed that an expert’s duty is to assist the court and overrides any obligation to the party paying the expert’s fee. It also warned that lawyers have a responsibility to ensure proposed experts understand and can meet that duty. The court noted that calling an expert who fails to do so may have consequences for costs, including in some circumstances orders against non-parties.