This from CQ:
" I think that we have known of a handful of recovered chemical-weapons shells, but not 500. That number has more significance. An artillery company could have laid down a very effective attack on an enemy position, quickly killing or disabling them in a manner outlawed for decades. Of course, that had been the entire point of the UN Security Council resolutions -- to strip Saddam of that capability -- and he obviously retained it, and lied about it.
The next question will be why the White House did not release this information at the time of their discovery. Santorum's statement says, The information released today proves that weapons of mass destruction are, in fact, in Iraq[.] It is essential for the American people to understand that these weapons are in Iraq. I will continue to advocate for the complete declassification of this report so we can more fully understand the complete WMD picture inside Iraq. That implies that a broader analysis of WMD in Iraq exists -- and that it differs significantly from the common understanding shown thus far.
Some will claim that the release is strictly for political purposes. They may have a point, but I doubt it will have anything to do with domestic politics. If Bush wanted to use it for that, he would have done so in October 2004 and not in June 2006. This information changes the picture about our pre-war intelligence in time for the Iranian confrontation -- and I suspect that the White House wants to declassify it in order to convince European leaders that our intel actually paid off."