Data released by a Washington D.C.-based research group shows dozens of facilities across the Chicago area store or use toxic chemicals which – if released in an accidental leak or explosion – could directly affect hundreds of thousands of schoolchildren throughout the city and suburbs, NBC5 Investigates has found. Many local schools are in the “vulnerability zones” of four, five – even six – area facilities. But there has been little way for any family to find out if their child’s school is in one of these zones – until now.

To find out if your child's school is in one of these areas, click here.

Emergency tapes from a chemical disaster in the Houston suburb of LaPorte last week, reveal the Dupont shift supervisor who called 911, was himself unaware of what was leaking from his plant, and what dangers arriving emergency crews might face.

Four workers died in the accident. And it was not an isolated case.

On the evening of April 17, 2013, a massive blast at a fertilizer company in West, Texas, killed fifteen people and injured 160 others. The explosion shattered windows seven miles away, and damaged or destroyed 150 buildings, including three schools. One of those schools -- West Middle School -- sat right next to the company.

According to a new report by the Washington, D.C.-based Center for Effective Government, schoolchildren all around the country, including hundreds of thousands here in Chicago, are attending classes every day in buildings located in “vulnerability zones.” Those are areas -- defined by companies that make or store toxic chemicals -- that could be in danger if the company ever suffered a catastrophic accident, leak, or explosion – similar to the one in West.

CEG has released an interactive map where you can search for your school or daycare center – even explore your home and your neighborhood – to find the facilities which have stated that you could be exposed to their toxic chemicals in the event of a major accident. The facilities range from chemical companies to water-purification plants to storage sites, and the range of potentially-affected schools and neighborhoods creates a dizzying map of vulnerability zones that cover a wide swath of Chicago, and suburbs ranging from Warrenville to the west; Frankfort to the south, and Hobart, IN, to the east.

“One in three students in the United States attends school in the vulnerability zone of a hazardous chemical facility,” says CEG’s Sean Moulton. “Nineteen point six million students go to school inside one of the vulnerability zones that we tracked.”

Due to security concerns, the EPA has not put the information online. Citizens wanting to see the chemical reports, have to go to an EPA office and ask to see them.

CEG checked out thousands of the reports at EPA reading rooms, and put the information online. The map shows that -- especially in urban areas -- nearly every school lies within at least one danger zone, and many find themselves in the overlapping jurisdiction of multiple plants.

Take PVS Chemical Solutions, Inc., a chemical manufacturer located on Chicago’s far south side. PVS – like every company that stores or uses dangerous and toxic chemicals -- must report those substances to the U.S. Environmental Protection Agency, with details on amounts, emergency plans, and how much of the surrounding area could possibly be affected if one of the chemicals were accidentally released in a major catastrophe.

According to its most recent EPA report made available to CEG, PVS stores large amounts of three different toxic chemicals at its site on Carondolet Avenue: 1.5 million pounds of sulfur dioxide (SO2); nearly a million pounds of Oleum; and 55,000 pounds of ammonia. According to CEG research, PVS tells the EPA that its “vulnerability zone” – the surrounding area that could be in danger in the event of a major accident -- is 25 miles.

Just half a mile from the PVS chemical plant is Virgil I. Grissom Elementary School with 328 schoolchildren. A mile-and-a-half away are both George Washington High School and George Washington Elementary School, with a total of 2,342 schoolchildren. Those are the three closest schools. But, according to the CEG research and mapping, there are a total of 1,347 schools in the Chicago area within PVS’s 25-mile “vulnerability zone,” with a total of more than 600,000 local students who could potentially be affected in the event of a catastrophic leak or explosion at PVS.

If those children were exposed to SO2,, they could exacerbate their asthma or struggle to breathe, according to the Centers for Disease Control. Exposure to Oleum (fuming sulfuric acid) can cause coughing, gagging, chest pain, fluid in the lungs, burning sensations and possible suffocation, and the mist also can severely irritate a child’s eyes and skin. And ammonia can cause burning in the nose, throat and respiratory tract (if inhaled), and (on contact) burns and eye injuries.

In north suburban Gurnee, Spaulding Elementary School sits just six tenths of a mile from a plant which has a vulnerability zone of ten miles. But when NBC5 Investigates showed that data to school superintendent John Hutton, he said it was the first he had ever heard that volatile materials were close to any of his schools.

“We really need to take a good look at our emergency preparedness,” he said. “We’ve talked a little bit about it. But it’s not been enough.”

Hutton noted every school has plans to take shelter from severe weather, or evacuation plans which might require location to a neighboring school. He said there are no plans in place which would relocate children outside such a large evacuation area.

“You know, a tornado, what’s the likelihood of that? What’s the likelihood of any disaster? It’s almost zero. But it happens. Everything we know about, we try to practice it.”

Now, he says, he believes it is incumbent on his district to drill for the potential of a wide-scale evacuation.

“Actually get them on buses and move them to that part, because the more you practice it, the more comfortable people are with the evacuation process,” he said. “The better we’ll be at it.”

The list of hazardous substances in close proximity to Chicago area schools is long. Another toxic chemical – required-reporting to the EPA – is highly-concentrated hydrofluoric acid. In the event of a massive leak or explosion, “even small splashes of high-concentration hydrogen fluoride products on the skin can be fatal,” according to the CDC. According to EPA records and the CEG report, one facility that houses hydrofluoric acid is PDV Midwest Refining, a petroleum refinery in southwest suburban Lemont. The CEG map reveals 702 schools and a total of nearly 350,000 students that could be affected by a catastrophic accident at PDV, according to documents the company filed with the EPA.

Another example: A bleach-manufacturer in west-suburban Willow Springs, owned by Rowell Chemical, stores more than 2 million pounds of chlorine gas, which can cause anything from wheezing and coughing to pulmonary edema if inhaled in large amounts. In its report, CEG provides the company’s documents submitted to the EPA and says the manufacturer has determined that its “vulnerability zone” is a 14-mile radius around the facility. CEG determined that 396 schools, with more than 180,000 students, are within that radius and could be affected if a chemical disaster were to occur at that plant.

It’s important to note that every one of these local companies has filed extensive safety plans with the EPA, which can be accessed on the CEG interactive map by clicking the location of the company, then clicking on the link for more information. Those filings also show that most facilities have never had any kind of mishap. The filings also detail a variety of emergency scenarios and prevention plans designed to make sure that things remain safe both inside outside each facility.

The chief of the United States Chemical Safety Board, the agency which investigates chemical accidents in the U.S., applauded CEG for putting the information online. He noted that his agency investigates more than 220 explosions and fires in chemical plants every year.

“The EPA was supposed to make these available to communities so they would know the level of risk,” said Rafael Moure Eraso, CSB chairman. He noted that due to security concerns, EPA has required actual visits to their offices to view the data.

“It’s not an easy way to find out this information.”

Now, he said, the question is what citizens will do with the knowledge that their schools lie in close proximity to such toxic chemicals.

“What are we going to do to reduce the risk of vulnerable places?” he asks, suggesting that communities, companies, and citizens should work together to determine how to proceed if a disaster occurs. And he believes that conversation should include debate about whether alternative chemicals could be used.

“Do we need to have this chemical in the community?” he says citizens should ask. “Do we need to have this much chemical in the community?”

Eraso suggested that the very legislation which required the filing of the reports, envisioned such discussions, and debates about where critical facilities like schools and factories should be located. But the information was never disseminated to the wider public.

“Like happened in West, Texas,” he notes. “They built a school a half mile away from the plant, simply because the land was available!”

In a written statement, the EPA says the information filed by these companies – and used by CEG to create its report – “is designed to protect against worst-case scenarios.”

And the American Chemistry Council has released a statement in response to the CEG report, saying in part: “There has been great progress in enhancing the safety and security of chemical facilities across the nation.” It points to its safety program called Responsible Care, and says that companies in that program “have reduced the number of incidents that resulted in a product spill, fire, explosion or injury by 55 percent since 1995.” None of the Chicago-area companies would offer direct comment on their vulnerability zones, when contacted by NBC5 Investigates.

Still, for parents of children in schools such as Ideal Elementary School in Countryside, the information provided by the CEG mapping can be eye-opening: Ideal is located within the “vulnerability zones” of six separate facilities with toxic chemicals – including PVS and PDV; the facility in Willow Springs; another facility in Lemont; and facilities in Lyons and Argo. The same holds true for 14 other schools in the area, according to the interactive map – they’re all within the reach of six separate facilities, in the event of a major accident. And they’re surrounded by hundreds more schools, all located in the vulnerability zones of four or five local toxic-chemical facilities.

The entire CEG report can be read or downloaded at the organization’s website.