If the FBI and CIA found the real cause, they could have released all the evidence. Having a valid cause of action (due to new evidence) means you can ask them

If the FBI and CIA found the real cause, they could have released all the evidence. Having a valid cause of action (due to new evidence) means you can ask them to release all the evidence now (or at least let the attorneys see it). Remember: discovery is the starting-point of the investigation, not the end. To refuse discovery, the government would have to cite some other reason (e.g., national security secrets incidentally involved, like disclosing the location of the test site). But while those reasons might have been sufficient when those programs were active (and capabilities unknown) 20+ years ago, it's unlikely those reasons are still valid now, because the secrets don't convey any current capabilities. And the political will to hide them might also have changed. So if the system works, they can hide when needed, but now they should provide all the information gathered and sequestered.