[Cooper:] The death toll is rising again from that massive explosion at a chemical warehouse in China's port city. At least 50 people have now lost their lives. More than 500 others are hospitalized. CNN's Will Ripley is there for us tonight. What's the latest, Will?
[Will Ripley, Cnn Correspondent:] It is understandable, Anderson, that people here in Tianjin are fearful of an explosion. When you see the kind of damage that it did to this car and to this building sitting more than a mile away from the blast site. There is a bio-chem team on the ground here right now. And what they're trying to figure out, it's how much air pollution and water contamination is there. Because this is a city of almost 13 million people. And the chemicals that there are they are mixed together they're still trying to figure out. The fact that they could launch a projectile, like that, they could blow the windows out of so many buildings here in the city. People are very fearful, and they are fearful of what they're breathing in. There was a huge smoke plume off in the distance yesterday. Just beyond those buildings, you can see today, it's no longer visible. But we can still taste and smell the chemicals in the air, Anderson.
[Cooper:] You can still smell them, that's incredible. How is the Chinese government responding to this?
[Ripley:] President Xi Jinping has been promising a transparent and open investigation into what happened. But we are seeing indications that that is not necessarily the case. A lot of social media posts critical of the Chinese government have been deleted. And even video of an incident yesterday where we were accosted while reporting outside of a hospital by a group that included civilians, but also security officers in uniform. That has been censored by the Chinese government as well. So, it appears as if they're wanting to give people answers, but perhaps not, not, not answers to everything. At least that's the suspicion on the ground here.
[Cooper:] All right, Will Ripley. Will, thanks very much. A troubling question now is ISIS using chemical weapons? The United States is investigating what it believes are credible reports that ISIS fighters use a skin burning mustard agent in an attack against Kurdish Peshmerga in northern Iraq earlier this week. Now, this comes from several U.S. officials all of whom stress more intelligence is being gathered to find out exactly what happened. Our chief national security correspondent Jim Sciutto joins us now. So, about this attack how particularly, how does the U.S. believe that ISIS could have obtained chemical weapons?
[Jim Sciutto, Cnn Chief National Security Correspondent:] This is an extremely powerful chemical agent. It dates back to World War I. Outlawed, in fact, after World War I. These Kurdish fighters, who were attacked with it, they show breathing problems with also evidence of a blistering agent, blisters on the skin. That's a telltale sign of mustard gas. And two explanation as to how they could have gotten it. They could have either overrun weapons caches, old Iraqi, or old Syrian weapons caches on either side of the border. Or U.S. officials say it's possible they've developed the ability to make mustard gas and put it on the end of a, mortar shell. Both of those explanations are bad, obviously.
[Sciutto:] It would be significant increase, expansion in the ability of ISIS to carry out attacks on the battlefield.
[Cooper:] Yeah, I mean, if in fact this is confirmed. I guess then another question is, how does it change the equation for U.S. coalition against ISIS for U.S. intelligence services operating in the area, for instance?
[Sciutto:] What U.S. officials say in terms of a battlefield weapon doesn't change the calculation on the battlefield too much. Of course, ISIS is going to be overpowered by U.S. coalition air strikes et cetera. But it's a weapon of fear. Like terrorism, like the beheadings. And that has an enormous effect on the battlefield. And then, of course, if the U.S. considers putting U.S. troops on the battlefield, that's something that General Odierno, the outgoing Army chief of staff, mentioned yesterday, that he would recommend. This, of course, would add to the dangers that they would face on the ground.
[Cooper:] Jim, I appreciate the update. Jim Sciutto. Just ahead, thousands of federal air marshals were recruited since the 911 attacks to keep everybody safe in the skies. The question is how well can they do that when they say they're stressed out, chronically sleep deprived and in some cases taking pills and drinking? Details ahead.