A worker claimed that after he was exposed to fumes from “sweet gas,” he experienced nausea, vomiting and difficulty breathing. But his workers’ comp claim was denied. And the Appeals Commission upheld the denial. The worker needed to prove that exposure to the fumes caused his symptoms. Although the timing between the exposure and the appearance of the symptoms was relevant, it alone didn’t prove causation. And in this case, the fumes could’ve simply exacerbated the worker’s underlying gastroesophageal reflux, concluded the Commission [Decision No: 2012-493,  CanLII 30672 (AB WCAC), May 31, 2012].