A toxic tort case is a causation case wearing other clothes. This article explains why proving that a chemical made someone sick is fundamentally different from proving that a car ran a red light, and what a claimant actually has to establish. It walks through the two causation questions courts separate — whether the substance can cause the disease at all, and whether it caused this person's disease — and why plaintiffs who conflate them lose. It covers the exposure evidence that is almost always the weakest link, how epidemiology gets used and misused, and the expert admissibility fight that decides most of these cases before trial. Later parts address latency and the discovery rule that keeps decades-old exposures alive, medical monitoring for people who are not yet sick, the aggregation problem that has driven mass torts for forty years, and how environmental statutes interact with private claims. Worked examples run throughout, and the article closes with what to do in the first month after a suspected exposure.