Plot hole: To rig blackjack card shuffling machines to make the dealer bust and everyone else get 20 or 21, its success would depend entirely on knowing the exact number of people at the table at that time. Perhaps the filmmaker is assuming all seats at the high-stakes blackjack tables would always be filled during a "soft" opening, but that seems extremely unlikely.
Plot hole: The rigged dice, while undetectable, wouldn't necessarily work. While they have the ability to turn the dice they still don't know what number the dice will land on and which way the dice will roll when triggering the lighters. Granted they can keep someone from losing by triggering the dice, they can't always make someone wins. And most of the bets that were placed (Rusty's Snake Eyes bet) are 1-roll bets, i.e. if you don't hit on that roll, you lose.
Answer: I don't think there's any way of providing an exact answer to this question, but I think it's safe to say that whatever materials they used were highly bacterial but not lethal (otherwise the 5 Diamond Award critic would be dead or in serious condition).
filledemot