Smoke & Mirrors

Officials also claimed that no water ran off from the plant, but now they acknowledge that thousands of gallons of potentially tainted water ended up in sewer systems, which ultimately flow into the Missouri River.

Recently, the EPA and the Occupational Safety and Health Administration fined ChemCentral a combined $560,260 for shoddy record keeping and failing to maintain safety standards at the plant. ChemCentral failed to notify the EPA of a deadly chemical kept there, the EPA claims, which could have hampered firefighters' ability to fight the blaze.

But in the six months since the fire, federal and local authorities have failed to address their own mistakes.

About an hour after the ChemCentral explosion, a twin-engine plane took off from a small airstrip in Waxahachie, Texas. The ASPECT (Airborne Spectral Photometric Collection Technology) plane was the EPA's best tool to determine whether the cloud was carrying deadly gasses across downtown.

It took two hours for the plane to reach Kansas City. By then, the massive cloud had churned 2,000 feet above the city. It was dusk, and the black smoke melded with the slate-gray sky. Ray Brindle, a former commercial pilot, was in the cockpit that day. He could see the well-defined cloud from 30 miles out. At 5:53 p.m., he steered the plane into a racetrack pattern to circle the smoke. "The fire was pretty spectacular," Brindle tells the Pitch. "Right away, we knew it was pretty serious."

Two sensors jutting out through holes on the belly of the plane began collecting data about the cloud's makeup. The plane's sensors pick up infrared energy, called photons, coming off the Earth's surface. When the photons pass through chemicals in the air, the chemicals interact with the photon beams. Scientists can then figure out what chemicals are present by analyzing the frequencies of energy absorbed in the air.

As the plane circled about 50 feet from the cloud, the data poured into an onboard computer station manned by the EPA's Baron Leger. The computer didn't tell Leger what it was picking up, only that data were coming in properly. The sensors can detect vapors from chemicals in a mile-wide area; on the computer screen, every pixel equals a foot and a half.

The ASPECT plane had been flying for just six years, but its crew had extensive experience collecting such data. After hurricanes Katrina and Rita, this same crew ran dozens of missions across the Gulf Coast to see whether there were dangerous chemicals in the path of flood waters. While flying over the Port of New Orleans, the crew once identified a single drum of chloroacetic acid, a chemical used in pharmaceuticals. The crew was able to alert officials on the ground about the drum before floodwaters engulfed it and contaminated the water with a potentially toxic chemical.

After four or five circles around the cloud, Brindle steered the plane westward. He needed to land the plane so EPA officials could decipher the data they had collected. But the cloud blocked the normal approach to downtown's Wheeler Airport. Brindle brought the plane in low near the West Bottoms, coming in at an angle to make the runway.

Waiting was EPA environmental scientist Mark Thomas, who grabbed the hard drive out of Leger's computer. Thomas brought the information to the EPA's lab in Kansas City, Kansas, where it took the computer 10 minutes to spit out a series of graphs. (The information produced in the EPA lab looked like a stock-market report, with peaks and valleys to help scientists determine a chemical's makeup.) Thomas then matched up the graphs to a book of chemicals, like comparing the lines in a fingerprint.

The process of matching up infrared charts to chemicals isn't perfect, so Thomas sent the charts to the Los Alamos National Laboratory in New Mexico. There, Robert Kroutil, a chemist who invented the ASPECT plane, did the same comparisons Thomas was making in Kansas. They got on the phone to compare notes.

Thomas and Kroutil found that the cloud contained low levels of three chemicals: ammonia, methanol and trimethylbenzene, or TMB. Thomas wasn't sure about TMB. "What is this stuff?" Thomas remembers wondering. Both of them hit their respective libraries to figure it out.

TMB is a chemical often used to make drugs and dyes, they learned. Exposure to it can affect the nervous system and cause fatigue. But based on the EPA's guidelines for exposure to TMB, the levels were low enough that scientists determined the cloud was safe.

By then it was almost 7 p.m. Thomas passed his findings on to EPA officials. The short answer: The plane had found nothing at hazardous levels in the cloud.

This was the first time that officials knew the cloud was safe for people in downtown. But Dyer had been telling the media for hours that there was no reason to fear the smoke.