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CAROL LIN, CNN ANCHOR: We want to bring you some fresh pictures now, in fact it might even be a live picture. There you go. It is a live picture out of Festus, Missouri, where HAZMAT workers are getting ready -- you can see them in the red suits there -- to go in. And what they're to do is identify the source of the leak in this train. It's a chlorine gas that's leaking out of this train. It was loaded with about 180,000 pounds of chlorine when it pulled up to this chemical plant.
And right now on the telephone is Dr. John Palmer with the American Chemical Society. Did I get that right, Dr. Palmer?
DR. JOHN PALMER, AMERICAN CHEMICAL SOCIETY: Yes, you did.
LIN: All right. If you can see this picture, can you describe to me...
PALMER: Unfortunately, I am not in a position to see it.
LIN: All right, let me describe it to you. I see at least two HAZMAT workers in orange suits on top of the car that contains the chemical. You've still got chlorine gas leaking out from the bottom portion of it. How would you describe they're going to try to attack this problem?
PALMER: Well, in general, they have to worry about the public safety, so the first thing they have done, obviously, was evacuate the area, which is a wise move. And then they worry about their own safety. The suits are a help, but they also have to have a practical way to shut off the leak, otherwise the best thing is to stand back and just protect the public from getting too close to it.
So I assume that what they're trying to do right now is decide if there is a hose or something, is there a shut off valve still working that they can contain the remainder of material in the tanker.
LIN: You know, and, Dr. Palmer, it looks like they might be having some success, because the cloud is beginning to thin out. The chemical is now -- you can barely see a trace of the cloud coming out from underneath the car. So it looks like they were able to locate, or at least seal up that hose connection. That is good news.
PALMER: Yes, they have methods -- the HAZMAT workers have methods to either apply a patch or to, again, if they manage to find a valve, to shut off the valve. And that would be the normal procedure.
LIN: Now, still though, you can see the chemical cloud. It appears to be laying low to the ground rather than dissipating up into the atmosphere. You can still see evidence of that cloud on the ground. For what distance is this cloud still dangerous?
PALMER: Well, it can be for many hundreds of yards away probably. Chlorine gas is about two-and-a-half times heavier than air, and so it will lay low to ground. And so, as the wind slowly picks it up and dilutes it, that cloud will dissipate, or that low- lying cloud will dissipate.
Certainly, chlorine in a high concentration can even be deadly, obviously, but at lower concentrations, it's a problem down to about a part per million. So I'm sure they are out monitoring at distances away from this leak and making sure that it's safe for people to be in the areas that they are checking.
LIN: About 50 people had to be checked out in hospitals, because they were having breathing problems. How close were they likely to the chlorine leak?
PALMER: Well, if they were experiencing breathing problems -- people that are very sensitive to materials in their lungs might have had that in fairly low concentrations. They probably were still, I am guessing, several hundred yards away or even further away than that. And you have a little bit of an acid burn in your mouth and your throat when you breathe a gas like this. And so I'm guessing that's what they were experiencing was that bite in their throat.
And as long as they got away from it and started breathing clean air and getting a little oxygen, they're probably going to be OK, but I'm sure they're under medical surveillance.
LIN: Well, certainly since we took the picture, the live picture there, these HAZMAT workers made quick work of their duty on top of that car. They have now left the scene there, and it appears that the cloud is completely dissipated.
Dr. John Palmer, American Chemical Society, thank you very much for joining us.
PALMER: You're welcome.
LIN: All right, Dr. Sanjay Gupta, our very own medical correspondent up in New York.
Sanjay, we were just hearing that some 50 people are being treated for inhalation problems. Do you think these people are going to have any permanent damage? It appears that we don't...
SANJAY GUPTA, CNN MEDICAL CORRESPONDENT: I'm sorry, Carol.
LIN: Oh, there we go.
GUPTA: I'm sorry. I didn't hear the question.
LIN: Oh, I just wanted to find out, now that it appears that they have been able to seal the leak, fortunately -- we're just getting a view of the nearby mobile home park there. I'm wondering, some 50 people had to be treated at the hospital for breathing problems. Do you think there's going to be any permanent damage?
GUPTA: It's very unlikely, Carol. Typically, the type of concentrations of chlorine, even though we saw that pretty scary looking cloud of gas, the type of concentrations that you need are pretty high within the air. And the good thing is that as soon as that chlorine actually gets outside the leak site, it actually dissipates or sort of gets diluted pretty quickly.
So besides some irritation to the eyes, the nose, the mouth, things like that, it's unlikely that they will have any permanent effects. The permanent effects that we're concerned about, of course, would be more permanent effects to the lungs. Actually that same gas, that burning actually causing scarring of the lungs, which would cause more permanent damage in the long run, but unlikely statistically that that would happen.
LIN: Well, that's good news indeed.
All right, well, you watched it live as HAZMAT workers were able to seal off that chemical leak. Chlorine is no longer flowing into that mobile home neighborhood adjacent to that chemical plant. And all looks well for now in Festus, Missouri. Breaking news there.
Thank you very much, Dr. Sanjay Gupta, for joining us from New York.
GUPTA: Thank you.
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