MS. DIANE REHMThanks for joining us. I'm Diane Rehm. Authorities fear dozens could be dead after a huge explosion at a Texas fertilizer plant. In Boston, officials continue investigating deadly bombings on the day of the marathon. And the FBI arrested a Mississippi man suspected of sending letters laced with toxin to President Obama and others.

MS. DIANE REHMJoining me to talk about the tragedies and investigations: Michael Greenberger of the University of Maryland Center for Health and Homeland Security, Ron Fournier of National Journal Magazine, and Roger Cressey, a counterterrorism expert who served in the Clinton and Bush administrations. Do join us, 800-433-8850. Send us your email to drshow@wamu.org. Follow us on Facebook or Twitter. Good morning, gentlemen. Thank you for being here.

PROF. MICHAEL GREENBERGERGood morning.

MR. RON FOURNIERGood morning.

MR. ROGER CRESSEYGood morning, Diane.

REHMWhat a week it has been. Ron Fournier, do we know what caused the explosion at the fertilizer plant in that small town of West Texas?

FOURNIERNo, we don't. What we do know is a town of about 2,800 people is devastated. We have homes that have been wiped from the face of the earth. We have five to 15 people dead. We have several dozen injured. And we have a crime scene. They're calling it a crime scene out of the abundance of caution. They have no reason to believe that it was done intentionally. Their suspicion is that it's an industrial accident, but, because of the times we live in and because in any investigation, you prepare for the worst case scenario, they're treating this as a crime scene and will rule out nefarious acts along the way.

REHMThe date, in and of itself, is relevant, Ron.

FOURNIERCertainly could be. It certainly is eerie. Tomorrow is the anniversary of the disaster at Waco, that Branch Davidian disaster. And obviously, that has roots to anti-government feelings in this country. And when this happens at the same time, we have the bombing in Boston and ricin attack coming out of the South, it makes people very concerned.

REHMRoger Cressey, why are fertilizer plants so dangerous?

CRESSEYWell, Diane, the chemicals involved in creating what has been described by some as a dual-use product -- I mean, it's used for obvious reasons in fertilizer for agriculture and a whole host of other things, but there is a explosive component and nature to it, particularly when gases are concentrated in an enclosed area. And what we've seen in the terrorism world is that fertilizer has been used in the past to help as an accelerant and as an explosive agent in terrorist attacks.

CRESSEYSo while this is certainly not that right now, there is a -- there's real concern from a safety and security perspective. And I think what you'll see in the investigation -- as Ron said, a criminal investigation is going to be part of this -- is what were the safety and security precautions in place here? What was missed, and why was this type of event allowed to take place?

REHMAnd, Michael Greenberger, how unusual is it that this should be called a crime scene even in the face of any actual evidence to that effect?

GREENBERGERWell, as was previously said, there's a lot of coincidences here on top of the Waco siege, which was on April 20. Timothy McVeigh, two years later on April 20, using fertilizer as part of his explosive construction, and later we find out his complaint was about the Waco siege. Two years later, he blew up the Oklahoma City courthouse. Now, you know, again, this is all supposition. I'm sure it's got the FBI and ATF alerted, but there's a lot of what we hope our coincidences here that catch the eye. And besides this being a very explosive chemical component, it also has gases that are suffocating in nature.

REHMAmmonia.

GREENBERGERYes, ammonia. So it's not just that there's been this explosion, which has been tragic, but one of the reasons -- they had a second tank that they were worried about, that it would go off too. But also, if you're too close to this, you're going to have respiratory problems, and you may need a ventilator or some other breathing assistance. So it's very challenging.

GREENBERGERThe other thing as was said the other day when we talked about this, the FBI has tripwires for nitrate, people who buy nitrate because of the Timothy McVeigh experience. Well, here, somebody may have eliminated the middle man and gone to the manufacturing plant. Again, it is all supposition, but I'm certain that the FBI and the ATF are going to look very carefully to see whether this was a terrible industrial accident or something worse.

FOURNIERWell, let me draw a historical parallel to industrial accidents. On April 16, 1947, the deadliest industrial accident in U.S. history took place in Texas City, not all that far from this incident. Ammonium nitrate exploded on a vessel. Five hundred and 81 people were killed in that industrial accident. So we don't know what this is, but we do have this weird confluence of events, both terrorism-related and pure accidents, in mid-April.

REHMBut then the question becomes how unusual it is to have a fertilizer plant located so close to a school and houses. The Dallas media is reporting Texas regulators knew in 2006 the fertilizer facility had two 12,000-gallon tanks of anhydrous ammonia and was near a school and neighborhood. I mean, what sense does this make, Roger?

CRESSEYSo what happens often in an investigation even if it's not a crime scene, in the aftermath, people look at the circumstances and you say, wait a minute, where was the common sense here? We have -- we see all the time when people are looking to build, nowadays, hazardous facilities, and the first thing they do is they do an assessment of the security landscape.

CRESSEYWhat are some of the vulnerable areas, what are some of the schools that could be impacted, et cetera? And they look at blast radius and things like that. I think this is a case where you saw something that was constructed, and has been in place for some time, and there wasn't not -- a whole lot of thought given to the potential safety concerns here.

REHMWest Fertilizer Company of West Texas told Texas Commission on Environmental Quality permit reviewers that emissions from the tanks would not post a danger. That assertion was based on expected routine emissions, not the possibility of a catastrophic failure.

CRESSEYDiane, that's also a -- whenever you do the -- whenever a company does an analysis, they never do the analysis based on the worst-case scenario.

REHMOf course.

CRESSEYThey always do it based on scenarios that fit within what they're trying to accomplish. And because the worst case always is something that they have no control over and if they put that forward, they'll never get the approval of the permits and the licenses and community support to build any type of facility.

REHMSo that company was required to build a wall between the tanks and a public road to prevent vehicles from striking the tanks. So the company complied. On Dec. 12, 2006, the agency's executive director issued an operating permit for the tanks which already existed. So in other words, how much investigation and safety precautions are taken before such an accident can occur, Ron Fournier?

FOURNIERUnfortunately, we have found out, time and time again in this country, over the last 20 decades that action isn't taken until there's a catastrophe. We have labor laws in place and laws guiding workplace safety because of disasters in shirt factories in the early part of the 20th century in New York. So unfortunately, it takes, oftentimes, a lot of people dying before our institutions do their jobs.

REHMMichael.

GREENBERGERYeah. The other thing is when the permits were being -- were going through the bureaucratic process...

REHMExcuse me, Michael. Just to point out, several listeners have called to say the Oklahoma City bombing was April 19 and not 20.

GREENBERGERI'm sorry. That was my mistake. It was very close to Patriot's Day, which is April 20. But the -- none of the citizens in the permit process complained about this, which if we were in the middle of Boston, that wouldn't have happened. I just want to say also that the placement of chemical plants in dangerous areas is not unusual. I think it was 2004 the Department of Homeland Security did an assessment of the 15 most catastrophic terror-related attacks.

GREENBERGERFirst was the use of a nuclear weapon. Secondly was explosions of chemical plants. And the example they used were chlorine plants in Northern New Jersey which, if exploded, would spread chlorine over a tri-state area affecting millions of citizens. You know, we have -- as Ron said, we have known about this being a danger. There's been efforts made to improve the safety.

GREENBERGERIt has been resisted by the plant owners. And so this is not something that just was going to happen in West Texas. We're exposed all over the country. And this final thing I would say, in Boston, there is what is called the BSL-4 laboratory where scientists experiment on the most deadly pathogens, and there was a leak out of that BSL-4 laboratory that absolutely drove the citizens of Boston crazy.

REHMMichael Greenberger of the University of Maryland Carey School of Law. Short break. We'll be right back.

REHMAnd we've been talking in our first segment about the Texas explosion in the small central Texas town of West. Ron Fournier, you said during the break it takes deaths for something to happen. Talk about the example you used.

FOURNIERJust -- again, to go back to the parallel to an industrial accident, this tragedy in 1974 that cost the lives of 580 people when ammonia blew up, that led to the first class action lawsuit against the United States in our country's history.

REHMAnd where was that?

FOURNIERThat was in Texas City. And more than 8,000 people got money out of that lawsuit, 8,000 victims or people related to victims.

REHMWould you expect that as a result of this explosion in West, Texas, there will be a class action lawsuit?

CRESSEYWell, if the investigation concludes that there was negligence on the part of the company here, then you can just well be guaranteed of that.

REHMWhat's negligence? How do we define negligence, Michael?

GREENBERGERWell, if a reasonable standard of care was not used by the company in using this or manufacturing this very dangerous chemical-oriented explosive, if they didn't follow a standard of care that's expected, that would be...

REHMBut what about the location of the plant itself?

GREENBERGERThat would all be taken into account...

REHMI would certainly hope so.

GREENBERGER...as to whether there was a -- it was standard of care that a reasonable person would use under the circumstances.

REHMOK. Go ahead, Ron.

FOURNIERI was just going to say the problem there, though, is the state regulators knew where the plant was and there was some mitigating action taken. This -- the people of the city obviously knew where the plant was. It took up a big part of the city. So I don't know if the location itself would be a problem for the owners, if -- again, we're assuming for the sake of argument -- this was an industrial accident not a crime.

GREENBERGERYeah. I just...

FOURNIERBut if they didn't take mitigating actions, that there were, like, the right kind of barriers and that kind of thing, that obviously could be a problem.

GREENBERGERExactly. The state could've expected a standard of care. And when you look at it, it wasn't followed and nobody expected them not to follow what the state permitting would've required.

REHMI see. All right. There's another incident in the news that has contributed to unsettling people. Tell us about the letters believed to have been laced with toxin, Roger Cressey.

CRESSEYWell, Diane, what we know so far is that there has been an arrest, and the arrest is related to an individual who is believed to have sent at least two letters, one to Sen. Roger Wicker from Mississippi and the second to President Obama, laced with ricin, a deadly substance.

REHMI thought there was a third to a member of Congress in Alabama.

CRESSEYYes. And there -- I think there is a safe bet to conclude there's probably additional ones this individual may have sent as well. The good news here -- I think this is a good news story -- is that since 9/11, we have put in place layers of defense, for lack of a better word, in dealing with mail delivery to the federal government. And what we're able to do here is to identify these substances very early on in the delivery process. So there's really no chance of these letters ever making it to their final destination.

REHMAnd joining us by phone from New Orleans, bioterror expert Gary Cecchine of the RAND Corporation. Gary, good morning.

MR. GARY CECCHINEGood morning, Diane. It's my pleasure to talk to you.

REHMTell us about ricin. Where does it come from, and just how dangerous is it?

CECCHINEWell, ricin is a toxin that's chemically extracted from castor beans. And castor beans grow on a plant that is fairly ubiquitous, grows in hot areas, particularly in the Southwest of the United States, but is also invasive. You can find it in New Jersey. It does not tolerate freeze well, so you don't find it much farther north than that. And basically the castor bean itself is toxic. If you were to eat a castor bean without breaking the envelope of the bean, the seed itself, it would just go right through you.

CECCHINEIf you break the bean and you eat enough of them, it becomes toxic. It becomes a bioterrorism agent depending on how you extract the ricin from the beans. And there are several ways that we won't get into on this program about how you particularly do that. But it's fairly well-published, and it's become kind of a cause célèbre, if you will, of some fairly wacko groups that (unintelligible).

REHMSo it clearly can be weaponized. But weren't we also looking at ricin as a way to combat certain cancers?

CECCHINEAbsolutely. Yes. The way ricin -- the ricin toxin works is when it gets into the cells of your body, it prevents your body from producing the proteins that you need to live, which is exactly what cancer cells do. They produce proteins that aren't good for you. And so it has been investigated as a potential way to target cancer cells.

REHMAnd how...

CECCHINEAnd -- I'm sorry.

REHMGo ahead.

CECCHINEI was going to say -- and I would point out that, you know, castor oil has been around for many, many years. People might remember, you know, children of the '40s and '50s taking a spoonful of castor oil to help their digestion.

REHMSure.

CECCHINEAnd, in fact, it's been found in ancient Egyptian tombs.

REHMSo how easy is it for someone to get hold of and then weaponize ricin?

CECCHINEWell, it's rather easy to get a hold of because it grows in low-lying areas that are well-drained and have a lot of heat. I mean, you can find those beans. Weaponizing it is a different issue, and there are different ways to do that to different levels of purity. The initial indications -- and this is an ongoing investigation, so I don't have all the facts and don't want to speculate more.

CECCHINEBut my suspicion is that the preparation that was sent in these letters is probably pretty crude as in just ground-up beans. I would also point out that it's not clear, I think, to most experts whether you can actually make somebody sick from putting ricin into a letter. It's most deadly if it's injected and then second most deadly if it's ingested.

REHMI see. Now, how does ricin differ from anthrax, which we saw in the last round of these kinds of nefarious, poisonous letters being sent?

CECCHINEWell, I sometimes refer to ricin as the poor terrorist anthrax. The main difference is that anthrax is actually microorganism. And it creates spores, so it's very resilient in the environment. And the people that we're sickened by those letters were sickened because they ingested those spores, which then propagated, grew within their bodies and killed them.

CECCHINERicin is actually just a chemical. Even though it comes from a biological source, it really is just a chemical. And it's also very sensitive to nature. So when the temperature is above 80 degrees or so, it -- what we call denatures, it is no longer as toxic as it would be, same with sunlight and other things that can affect it. So this is, compared to anthrax, a very smaller threat.

REHMSo what you're saying about anthrax is that if you simply opened an envelope containing anthrax without touching it that the spores themselves would somehow emerge from that envelope and could be ingested without -- with just your breathing the air around that envelope, which is not the case with ricin.

CECCHINEThat's true. And with the anthrax, it depends on to what size those -- the anthrax formulation has been milled, as they say, or ground up.

REHMI see.

CECCHINESo if it's very small, it's very easy to inhale. That's not really the case with ricin. It is possible to make a ricin dust, if you will. But inhalation is much less problematic than it is with anthrax.

REHMRoger Cressey wants to add a point.

CRESSEYWell, Diane...

CECCHINEPlease.

CRESSEY...to follow up on what Gary said, if you go back to the anthrax attacks in 2001, you had hundreds of staffers and members of Congress in the Hart Office Building who had to go on Cipro because of concern that the anthrax spore has got into the air-conditioning system and was -- and traveled throughout the building.

CRESSEYSo the ability of anthrax to attack a larger population is a much higher concern. As Gary said, when I was doing counterterrorism in government, we didn't worry about ricin as a significant threat because of the reasons he just described.

REHMNow, have the letters that came to the president to the other members of Congress been confirmed to contain ricin? We don't know, or do we, Gary?

CECCHINEIt's my understanding that there has been an initial identification. It normally takes 24 to 48 hours to really confirm Ricin, and I know they're doing that with my former colleagues up at Fort Detrick at this moment. Generally, the initial screening is very sensitive, but not very specific. And so, you know -- particularly because this is an ongoing investigation. They just want to be as specific as they possibly can, and that may take another day or so to really nail that down.

REHMAnd, Gary, final question for you. I know you don't want to speculate, but do you, could you, see any connection between any of the incidents happening around the country -- the Boston Marathon, the letters to the president, members of Congress, the explosion in Texas -- do you see any connection whatsoever?

CECCHINEYou know, I really don't, and it's, you know, it's a confluence of coincidence in many particular cases. I was listening to the conversation earlier. I would also point out to you that April 20 is Hitler's birthday. So, you know, if the conspiracy theorists really want to go crazy, they can add that into the mix. We don't know. It is interesting that these letters were mailed shortly, we think, shortly after the Boston bombing.

CECCHINEIt might have been mailed before then. But -- which is similar to what happened after the 9/11 attacks and then the anthrax letters came out. So there's a certain what I would call a coattail effect, where people think that, you know, now the public is shaken up, it's time to do my crazy attack. But I -- you know, I'll leave that to the federal and local authorities to decide if these things are truly related, but I don't see any evidence that they are personally.

REHMRon Fournier.

FOURNIERI personally think there might be a tie to the fact that today is my mother's birthday, but that's just me.

CECCHINEWell, they...

FOURNIERNo, seriously, I think to pick up on a phrase you just used, law enforcement officials do think this was a crazy attack, that this was a gentleman -- they're identifying a guy named Paul Kevin Curtis, who in -- according to their investigation so far, and, of course, we have to be careful about buying into the early part of an investigation.

FOURNIERBut this is someone who's -- who was known to authorities as a letter writer and a conspiracy theorist and thought that the government was taking part in a organ conspiracy, organ trafficking conspiracy. He wrote in a letter -- in both letters, allegedly -- I'm KC, and I approve this message. So you have to wonder about the stability of a man who uses his own initials in the letter and a political ad slogan for his letter.

REHMRon Fournier, he's editorial director of National Journal magazine. And, Gary Cecchine, I want to thank you so much for joining us.

CECCHINEIt's my pleasure. Thank you, Diane.

REHMAnd you're listening to "The Diane Rehm Show." We're going to open the phones now, 800-433-8850. And before we do, the president and first lady have arrived in Boston to attend an interfaith service for the victims of the bombings. The service is set to begin at 11 a.m. Eastern time. Do we know anything more about those bombings in Boston? A camera at Lord & Taylor's in Boston, Michael, seems to have picked up something.

GREENBERGERYes, that's true. But I think if we've learned anything over the last 24 hours, it's not to draw conclusions too quickly. I am personally very satisfied with the nature of the investigation. I and I think there are others who have high degree of confidence that, ultimately, they'll be able to pinpoint the perpetrators. But it may not -- it may take a while. And I think everybody right now is best advised to leave the law enforcement investigators to their job.

REHMRon Fournier, yesterday, we had such confusion, various networks, various news organizations reporting a suspect had been arrested, and then withdrawing that allegation. What was going on?

FOURNIERWell, without going too deeply into the new media model, we now have -- I'm an old wire service reporter, as you might know. You worked for the AP for years, and we were trained and were brought up in a culture of being right first and first second. And we were very fast. We had to be. They still are among the fastest, but they're trained to be careful as they're being fast. Now, we have the democratization of media, where everyone is a journalist who has access to a computer, and it's really lowered the standards.

FOURNIERAnd what you saw yesterday was a lot of folks who should know better -- or a lot of folks who don't know better -- reporting the first things they heard from people who have a badge. And the funny thing you learn when you do the -- in this business long a -- a long enough time that even well-intentioned police officials often are passing on things they heard on CNN or things they heard in the break room or rumors that are going on in the police station.

FOURNIERAnd you have to be very careful and vet and double-check everything you report, even if you're hearing it from somebody with a highfalutin title. I know, on 9/11, I was part of getting something wrong for the AP, and I was part of us getting a lot of things right. But I was part of and played a big role in a mistake we made that day.

FOURNIERAnd I got that information -- I can't say who the person is, but it was a very high-ranking person in the White House who had every reason to have the right information and who had never led me wrong, but, on -- in the cloud of war that day, gave me some information that was wrong, and I passed it on to the people. You have to be really careful.

REHMRoger Cressey.

CRESSEYAnd for the record, I wasn't that individual.

FOURNIERHe's never helped me out, just for the record. He's never been a source.

CRESSEYSo I've seen this from both sides. I've seen it from being inside the government, and I've also seen it in my work as a news analyst for NBC. I think NBC, for example, did a great job yesterday. They were very reluctant not to hop on board once that initial report came out. The pressures on the media now to be first are so strong that, as Ron said, you see people make mistakes.

CRESSEYI think you also have to realize that a lot of the leaks that come out aren't from the primary source of information. It's from a secondary or a tertiary person who hears it from somebody else or reads it and then passes that on, and inevitably, something gets lost in translation sometimes. And in a fast-moving investigation like we're seeing up in Boston, we shouldn't be surprised by that. So remember the old adage from the Pentagon: The first report in war is often wrong.

REHMMichael.

GREENBERGERYes. Well, I agree with everything that's been said, but the other thing I want to say that I think is noteworthy is the FBI and ATF's and the fusion center's reluctance to try and -- and their caution in identifying somebody. They've obviously made some really bad mistakes in the past: Richard Jewell in the Atlanta bombing in 19 -- Olympic bombing in 1996.

GREENBERGERThe anthrax investigation, they pinpointed a doctor at Fort Detrick, Steven Hatfill, and he ended up suing and winning money from the government because the investigation was so bad. They then pinpointed a man named Bruce Ivins, who had committed suicide, and studies have shown that that conclusion was not good.

REHMShort break. We'll be right back.

REHMAnd welcome back. It's time to open the phones as we talk about what has become one of the worst weeks in April of 2013 that certainly is going to go down in history as one of the worst in our country. Let's go to Ocean Springs, Miss. Stephen, you're on the air.

STEPHENThank you, Diane Rehm. First of all, I appreciate the great work you do in having intelligent and timely discussions on events like this.

REHMThank you.

STEPHENYou are truly a national treasure, and I enjoy your show, Diane.

REHMThank you.

STEPHENSomething that I haven't seen pointed out in the media about this particular plant, and I've got some experiences, in that they were going to put a plant to processing fish in a neighborhood next to a school probably about eight years ago. And initially, the concern we had was the smell of the issue. And later on when we started investigating, they were going to be using several thousand pounds of anhydrous ammonia.

STEPHENAnd one of the problems that you have, particularly in the South, with this particular product is that -- at least it was eight years ago -- it was the only component that is not readily available that's used for cold cooking of crystal meth. And there were problems, you know, literally almost weekly where they -- 'cause there's not a lot of sources they can get this ingredient where people breaking in and stealing it.

STEPHENAnd, of course, when they're breaking and stealing the anhydrous ammonia, they typically don't take the time to close the tank back and do things like that. And the product itself is heavier than air and tends to stay close to the ground and has a tremendous health risk, particularly next to an old folk's home because it would cause evacuations. It could smother or kill people.

STEPHENAnd I just don't understand how even without the risk of the explosion that it would ever be acceptable to have large components of this in Texas which also has a crystal meth problems like we do in Mississippi where, you know, it's so commonly, you know, broken into and stolen because this is a component they have to have.

REHMAll right. And that's the question, was the plant there first and the town built around it, or was the town there and the plant came in? I have an email here, two contradictory perspectives. The first from Kirk in Florida said, "The West fertilizer plant was infringed on by the growth of the city of West not vice versa." On the other hand, Kate in North Carolina says, "The tragedy in West, Texas underscores the benefits of a need for comprehensive land use, planning and zoning." Ron.

FOURNIERWithout speaking directly to this town which we all don't know very much about yet, I can say generally having lived for a short time in a town this size and having studied a lot about rural America and business regulations that there is a cycle of acceptance in a lot of communities, cycle of dangerous acceptance, and it starts with the money that a plant like this brings in. And we can't ignore that.

FOURNIERWe can't ignore the fact that there's businessmen in that community who rely on that money and regulators and politicians who are sensitive to that money and reliant, in often cases, on that money, and then the public in that town which is reliant on the jobs that come from a business like that. So you have everyone who has incentive to put their hands over their eyes and over their ears and ignore the possibility and pray that something like this doesn't happen. And then when it does, they all point fingers at each other.

REHMAll right. To San Antonio, Texas. Good morning, Perry.

PERRYGood morning. Thank you for taking my call.

REHMSurely.

PERRYMy comment is about the gentleman who wrote the letters with the ricin in them. I heard -- I have heard on the radio yesterday and today that the man who was arrested had written many letters to this congressman, and that was why he was a suspect. I also write letters to my congressman as do others, and I think it should be clarified if he wrote threatening letters to his congressman or not, otherwise people might think if you write a letter to your congressman, you could be a suspect if something bad happens.

REHMPerry, I'm so glad you called with that point. Writing letters to members of Congress is something we do in a democracy, and I hope you will continue. The concern here is what might have been in those letters. All right. Let's go to Dallas, Texas. Good morning, Bryan. You're on the air.

BRYANGood morning, Diane. My question and just very quick comment was going to be about the fertilizer plant explosion. I think it should be clarified real quickly that police -- I actually work in TV news. I'm a producer. The police just wrapped up a press conference where they once again re-emphasized they don't believe this has anything to do with terrorism. But we actually have seen, not just here in (unintelligible) a lot of these type of explosions.

BRYANThere was one a few months ago in a suburb of Dallas, in Garland. A few years ago, there was one actually right next to downtown Dallas. There was another one near in Houston. So my question is, a lot of these plants, especially when near populations and there's generally fail or do poorly when it comes to safety checks, why don't local, state, federal bodies enforce the laws that are in the books right now and that way we can avoid tragedies?

REHMYou know, Bryan, I was in Dallas shortly after that explosion, so I do recall it, and I do recall looking out of one building at the remains of that other building in which the explosion had taken place. So the question becomes, why aren't federal officials taking more care about the placement of these plants?

GREENBERGERWell, first of all, I think Ron's assessment of the small town environment is absolutely right, and it's a terrific point. But I will tell you, when I was just in the Justice Department pre-9/11 worrying about these things, we had had the Bhopal incident in India. That had a very big effect on the regulatory environment here. But there is hand-to-hand combat between the people who own these plants, and as I said, there are terribly dangerous plants in New Jersey, Northern New Jersey as well.

GREENBERGERNow, it's almost irrelevant to some extent whether this was an industrial acts of terror because when it gests released, people are hurt very badly, and the resources of the communities are destroyed or stretched to their limit. So the question is, are be being careful enough in, for example, chlorine plants in Northern New Jersey? The public, really, I mean, we've said here, one of the silver linings here is it draws attention to the problem.

GREENBERGERBut on day to day basis in Northern New Jersey, people drive by these things and don't understand. As I said earlier, the Department of Homeland Security in 2004 listed the explosions of these plants as the second most dangerous thing that can happen. Now, it's true they were looking at terror attacks. But if this is an industrial accident, it could happen in a high populated area, and there is not enough attention being paid.

REHMAll right. To (word?), N.Y. Hi, Holly.

HOLLYHi, Diane. How are you today? Nice to...

REHMI'm good. Thank you.

HOLLYDiane, I'd like to post a thoughtful subliminal supposition. Well, I called and spoke with the tip line yesterday. I said this, where was the placement of the first bomb by the flags that I saw the police tearing them down? And in other words the placement of the first bomb, what flag was it placed by, be it a love or hate relationship with the bomber and the country of the flag? That's number one. And, number two, I think they're going after international because why is this video of the person placing the second bomb by Lord and Taylor, if you will?

REHMRoger Cressey.

CRESSEYSo it's an interesting concept as your symbolism in the attack here based on that. The bottom line is that we have made -- we, the law enforcement community has made some significant progress. And I believe we're going to -- we'll see pictures of the suspect or suspects 'cause there at least two. So we know this wasn't a traditional lone-wolf attack. There is a broader...

REHMWe know that.

CRESSEYWell, if they're looking for two suspects, then that's not -- it's a broader conspiracy.

REHMAnd that's what they've said.

CRESSEYThat's what we're hearing. So if that's the case, then immediately, they're going to be able to look through cellphone records, they're going to be able to go identify this individual and move quickly. And we're going to paint -- a picture is going to be painted very quickly of whether it was just one, two or more. And what is encouraging here is that the speed and skill of the law enforcement community on this is incredibly impressive. And we've -- that's not to say we're going to catch anybody real fast, it just means we're going to be able to identify the individuals extremely quickly.

REHMAll right. And what could authorities learn, Roger, from these pressure cooker pieces they'd found?

CRESSEYWell, they're doing a tremendous amount of forensics analysis right now. They're rebuilding the devices at the FBI facility in Quantico. But a pressure cooker device has been used for years as a tool of terrorism. It's been used internationally. It's been used in India, in Iraq, Afghanistan. This is poor man's tool.

REHMAnd yet you tend to think apparently that this was not connected to international groups.

CRESSEYThat's where my gut leans right now, but, I mean, I've -- someone from Massachusetts who's ran the Boston Marathon, who has looked at threat environments in my prior life, the idea of attacking the marathon, the iconic symbolism of that is to a very -- it's a subculture. It's runners, and it's New England.

CRESSEYWhat is the broader international theme there? Now, yes, there are over 59 nations that participate. So there are things here that just don't add up in a traditional way that we've looked at international terrorism. But ultimately, Diane, we're going to have to see where the investigation goes.

REHMAnd then there was a bomb scare at a Boston courthouse.

GREENBERGERWell, that was all the result of the reporting. There was a report that the suspect who is captured or under arrest was going to be taken to the Boston courthouse, or people were anticipating it so there was a massive crowd around the courthouse. And the next thing you knew, you had a bomb scare in the courthouse, which I think goes to the question of we shouldn't get ahead of the story. I think other thing people are worried about is what does -- what lies in the future, for example, like marathons?

GREENBERGERAnd I found it very instructive that the police commissioner of New York, Ray Kelly -- and New York is considered first among equal state of the art counterterrorism measures -- and he has said there's lessons learned here, and they're planning for the -- they're not going to stop the New York Marathon, but their planning is going to be changed. They'll be doing different things. Again, we said this earlier in the week, the law enforcement counterterror has been terrific.

GREENBERGERSome of it's been luck, but some of it's been very hard work. We have not had these rash of problems. Now, we've had it. People are saying, well, maybe we better do things. And New York City is articulating what they're going to do to be safer. And, look, that's the way things worked. These -- the Boston City police are great, but everybody's learned lessons for how to deal with large public crowds.

REHMRoger.

CRESSEYSo we need to be clear on one point, which is you cannot guaranty a 100 percent security on the marathon route. And it will never happen. What you can do is you can improve security, you can minimize the risk. And this is all about managing risk, Diane, when it comes to securing these type of events. At the starting line, at the finish line, security can, in theory, would be the greatest.

CRESSEYBut what if this bomb was planted at Cleveland Circle, at Coolidge Corner, at Wellesley? There are places there where you could have had a significantly higher casualty rate because the first responders wouldn't have been right next to it. So we'll be able to do things to improve the overall security.

REHMBut there are limits.

CRESSEYThat -- but there are always limits.

REHMAnd you're listening to "The Diane Rehm Show." To Winston-Salem, N.C. Good morning, Ryan. You're on the air.

RYANGood morning, Diane. Thank you for taking my call.

REHMSurely.

RYANAs you -- to speak to the general theme of your show, this kind of the worst week in history, my birthday falls tomorrow. I kind of see this as sort of a repeat of some of the things you were talking about earlier like Waco. But we also have Columbine, we have Lincoln's assassination, we have the start of the Civil War, we have the Revolutionary War.

REHMOf course.

RYANNow, I'm not a conspiracy theorist, but I did want to speak to the -- just the general need for -- that it seems humans have to look for a meaning, to look for a connection. I kind of agree with your guests. I think a lot of this is just coincidence. But maybe we can talk a little bit about what is this need for us to find a connection, and why is it important?

GREENBERGERWell, first of all, I think one of the great silver linings certainly out of the Boston Marathon situation, as was true after 9/11, is the coalition of people all over the country, and it's been talked about at sporting events. The New York Yankees played "Sweet Caroline," which is the Boston Red Sox song that they play. But that's just an example. There's been a broader, I think, bringing together of people.

GREENBERGERThis is not a partisan thing. And people are -- so I think when we're searching for meaning, I'm very impressed by the fact that we are resilient and people -- marathons are not going to be ended, and we'll go forward. But, you know, it's one thing to talk about Hitler's birthday or Lincoln's assassination. But to my mind, just like I don't want to draw conclusions about what exactly happened, I think the reason this is a crime scene and the FBI is involved is they can't disregard the fact of some of these anti-government episodes.

REHMExactly. Roger.

CRESSEYWell, Diane, we look for meaning 'cause we want to try and understand. Whenever innocents are killed and maimed, we have difficulty comprehending it. Why would people do it? And in any kind of terrorism investigation, it focuses on three questions: who, why and how. So we know the how now. We're getting close to the who.

CRESSEYThe why is going to be the one that always generates the most discussion and conversation. And sometimes that's the most difficult one to get our arms around. And, you know, we often talk about resiliency. And what you're seeing in Boston, what you're seeing elsewhere is a spirit of resiliency. And that, more than anything else, is what you take comfort in as a nation.

FOURNIERThere's also a great period of -- great sense of anxiety. And you just can't underestimate how it makes people feel to see a soft target like this hit. And with the lack -- the reason we want answers -- you're exactly right. Think about 9/11. Go back to how we were feeling then. And if we didn't know who did it -- what if we went for six months and we didn't know the who or the why?

FOURNIERThe fact of the matter is what help get us through that period, what gave us some resilience was right away we knew who the bad guy was, and the president of United States unleashed, you know, hell on Afghanistan. And we all felt better in a way because at least we were doing something. And right now, we're in this period where we don't know what to do.

REHMHowever, let us not forget the negative effects of the aftermath going into Iraq when there were no weapons of mass destruction. Ron Fournier of National Journal magazine, Michael Greenberger of the University of Maryland and Roger Cressey, former counterterrorism official in the Clinton and Bush administrations, thank you all so much.

GREENBERGERThank you.

CRESSEYThank you, Diane.

FOURNIERThank you.

REHMAnd thanks for listening. I'm Diane Rehm.