A federal appeals court has affirmed a lower court’s ruling requiring expert witnesses to demonstrate a causal relationship between exposure to substances and health issues in lawsuits from BP oil workers. The 11th Circuit Court upheld the dismissal of claims by two workers who alleged sinus problems after cleaning up the 2010 Deepwater Horizon oil spill. The court found that the plaintiffs’ experts failed to establish a minimum exposure level that would pose health risks and did not adequately identify connections between their conditions and the exposure to oil or dispersants. This ruling emphasizes the rigorous standards for expert testimony in toxic tort cases, reinforcing previous court decisions on similar grounds.