What are some mass destruction weapons in Iraq?

There were allegations that Iraq had weapons of mass destruction and considering that Iraq famously used weapons of mass destruction during the Iran-Iraq War, such an allegation was not preposterous.

By claiming Iraq had weapons of mass destruction, making it a threat to national security

There is no definitive answer to this - only theories. There was the claim that Iraq was building weapons of mass destruction. The Bush administration later abandoned that claim, and didn't offer anything in its place.

None.