The Federal Judge's ruling in Ohio District Court to allow a jury to consider issues about causation was significant because this was one of the first times the causation issue was allowed in front of a jury and because this judge is responsible for handling thousands of cases that have been put under her responsibility. Although the first trial did not consider the issue because the jury did not find fault with the defendant in terms of a failure to warn, so that the causation issue was not heard, this issue will be considered in future trials, and the presentation to and handling by the jury will be of great interest. Previously, a causal link to 'Parkinsonism' was generally not allowed to go to the jury because of the supposed vagueness of such condition, because of the various symptomatology patterns and other related syndromes, which could sometime be difficult to distinguish, and because it was argued that a toxic threshold of exposure had not been exceeded or had not been exceeded continuously for a sufficient length of time. Since that time research has shown that there is an underlying common physiological disturbance that can result from this type of activity, a toxic 'signature' that is believed to be most reliably tied to (excessive) welding fume exposure. It remains to be proven in court or through epidemiological studies (which to date have not been conducted) that exposure is sufficient to cause this disorder.