This is the question that stops many people from even asking — they assume that because the exposure was years ago, any claim must be gone. In toxic-exposure cases, that assumption is often wrong, and it is worth understanding why before giving up.
Toxic illnesses frequently develop and surface long after the exposure that caused them. If the deadline to file ran only from the date of exposure, people would routinely lose their claims before they even knew they were sick. To address that, the law in many situations uses a discovery rule: the deadline can begin when you discovered — or reasonably should have discovered — your illness and its likely cause, rather than at the exposure itself.
Whether and how a discovery rule applies depends on the state and the specific facts, so the honest answer is that it should be confirmed, not assumed in either direction. What is clear is that waiting carries risk — deadlines are ultimately limited, and evidence degrades over time. If you suspect an exposure made you ill, a free, confidential review can tell you where you actually stand.