The Romans had high levels of lead in their pottery. This was a particularly bad problem in wine vessels.
They also sweetened their wine with lead oxide.
As long as it didn't affect the lead in their pencils....I don't see a problem. 8>)
Lead acetate was also added to sweeten old wine, even though some Greeks knew centuries before that lead was poisonous.
This came out some time ago, and a liberal paper editorialized to the effect that: "Hey, we don't have to worry about moral causes for Rome's fall. It was all the fault of those pots."
Maybe the moral causes are overdone -- Rome in its heyday, centuries before the fall, was already quite immoral by modern Western standards -- but the paper's response looks a lot like a cop-out.
Their answer is similar to the current argument that the decline in crime over the last thirty years is a result of decreased use of lead paint. It's hanging too much on one factor. People do that because it gives them the answers they want, not answers that fit all the facts. More here on lead poisoning and the fall of Rome.
I don't know what caused Rome's fall, but one thing people have pointed to, is that once the crumbling started it was easy to opt out of the Roman system. As things began to fall apart nobles could simply retreat to their estates and live separate, self-sufficient lives.
One big reason Rome fell is that people didn't think they needed the big, domineering state, but could take their chances with the barbarians and whatever else came along.