It would have been the first case to go to trial in connection with a cluster of brain cancers among employees at the site, in Spring House, Montgomery County.
Lawyers for both sides declined to comment, citing a judicial gag order to limit pretrial publicity. Aaron Freiwald, the lawyer representing Snizavich's widow, has appealed the judge's ruling, but for now there is no trial.
Expert opinions must be delivered with a reasonable degree of scientific certainty, said Edward D. Ohlbaum, a professor at the Temple University Beasley School of Law.
The medical expert, physician Thomas H. Milby, wrote that he was reasonably certain that Snizavich's brain cancer had been caused by unspecified chemical exposures at the plant.
But Milby also wrote that the cancer "more likely than not occurred as a consequence of his work at [the] Spring House facility." In his ruling, DiVito singled out that phrase as problematic, writing that it "negated" the expert's required degree of certainty.
"We allow experts to do something that nobody else is able to do, and that is to state an opinion," Ohlbaum said after being told of the ruling. "We want to make sure that the expert's analysis is reliable, and that the expert came to that analysis by a reasonable degree of scientific certainty."
Certainty was elusive long before the Spring House saga entered the legal realm.
Rohm & Haas, now owned by Dow Chemical Co., conducted two internal studies that did not establish any cause for the cancers. But federal occupational-safety officials criticized the research as flawed.
Then in 2010, a University of Minnesota research team found that up to 14 employees at the Spring House site had died of brain cancer after working at the facility, which opened in 1963. At least two other people died of brain cancer after working there, but they were not counted among the 14 because they were not assigned to the site full time. About 5,200 people worked there during the more than four decades covered in the study.
Yet, as in the company study, the research team was unable to pinpoint any specific chemical culprits among the thousands that were used at the site.
Freiwald, the plaintiff's lawyer, has pursued claims for several Spring House employees before the Bureau of Workers' Compensation, so far without success. Snizavich was not an employee but a contractor, so Freiwald filed that case in Common Pleas Court on behalf of Snizavich's widow, Anne.
Snizavich worked for the Welsch Co. from 1982 to 1991, performing a variety of long-term jobs in pipe installation and maintenance at Spring House, typically working there for months at a time, according to the lawsuit.
The lawsuit cites a series of internal company memos indicating that officials had concerns about indoor air quality at the research site in the late 1970s and early '80s. An internal committee wrote in an August 1982 memo that some chemical vapors, once expelled by air-handling equipment, were being sucked back in.
The lawsuit maintains that Snizavich was never warned of any air-quality problems or that he should wear a respirator or other protective equipment.
The company has maintained that the amounts of various chemicals in the air were never high enough to pose a safety risk.
Contact staff writer Tom Avril at 215-854-2430 or firstname.lastname@example.org.