KANSAS CITY, Mo. -- Multiple explosions at a chemical distribution facility shook an industrial area of Kansas City on Wednesday afternoon, sending an ominous smoke cloud above the downtown skyline and prompting the evacuation of nearby schools, homes and businesses.

A fire captain and a plant employee suffered knee injuries while they were trying to evacuate from the Chemcentral facility in the northeast Bottoms. Both were taken to local hospitals. No other injuries were reported.

Officials advised for anyone within a one-mile radius of the plant to stay out of the area.

The fire raged for several hours and completely destroyed the chemical plant.

At a news conference Wednesday night, Fire Chief Richard "Smokey" Dyer said he expects the fire to die down by Thursday morning and then they will send in crews to extinguish it.

However, Dyer said "we're not out of the woods yet," and said that more explosions could occur at Chemcentral, which stores and distributes various chemicals and solvents.

Dyer said all air monitoring tests have come out negative.

"Every indicator we have is that the air is safe -- we don't know of any problems," Dyer said.

He compared our air to a "bad smog day on the West Coast," and said we're within federal air quality standards. However, Dyer said there are still irritating vapors close to the plant.

Chemical Drums Exploded

Authorities said nine employees were at the the Chemcentral site when several 55-gallon drums containing chemicals exploded, touching off more explosions and fires.

Plant superintendent Craig Nienhueser said that the fire started at about 2:20 p.m., when workers heard a hissing noise inside the building at 910 N. Prospect Ave. They went around to the back and noticed some flames, at which point the workers were evacuated.

Dyer said he believes that the fire started when some flammable liquid was released. It ignited and spread very rapidly, causing more explosions. He said the exact scenario that caused the fire isn't yet known.

"This fire spread very rapidly," Dyer said.

More than four hours after the fire started, flames continued to shoot from one large chemical tank.

NewsChopper 9's Johnny Rowlands reported that steam was seen coming from three, 30,000-gallon railroad tanker cars that are parked near the fire, and for several hours there was concern that they would explode. Officials said a volatile form of petroleum distillate was inside the tankers. If a tanker explodes, everyone must be at least a half-mile away to be safe, firefighters said.

By 7 p.m., Dyer said the fire had pulled back from the tankers.

"An hour ago, the fire was raging. Now, it's just a few pockets of fire," Rowlands reported.

Pictures from NewsChopper 9 showed that the fire had destroyed the company's warehouse and office building. The fire also consumed several tanker trucks.

Dyer said that Chemcentral is the only business that is reporting fire damage, however, a complete damage report won't be known until crews can get closer to the plant.

"We are just thankful everybody is OK. Now we just have to work with the fire department to get this contained," Nienhueser said.

Mandatory Evacuation Order Issued

The city's emergency operations center is up and running and will remain active to monitor the situation.

The city issued a mandatory evacuation order for everyone within a five-block radius of the chemical plant, including about 3,000 people who lived in area. Police officers are aggressively enforcing the order and are going door to door to make sure people leave.

"(The officer) said, 'It's either get out or get blowed to hell,'" said Jessie Ross, who works in the area of the explosion.

Roads in the area were also shut down and traffic was being detoured.

The Red Cross opened a shelter for evacuees at North Kansas City High School at 620 E. 23rd Ave. City buses were on standby at 3410 Nicholson St. for those needing transportation to the high school.

KMBC's Maria Antonia reported that the shelter is set up to accept up to 500 evacuees, but that currently there are fewer than 15 people checked in.

Some of the evacuees said they were upset that they were forced out of their homes.

"We were rushed out of our houses because of the explosion, and I didn't take any of my (heart) medication. I went back to the barricade, but (the police) said I couldn't go in to get it," evacuee Michael Rogers Sr. said.

Relatives trying to contact evacuees can call the Red Cross at 816-931-8400.

KMBC's Jim Flink reported that some residents refused to leave the Bottoms, and that the city will address the issue.

The Kansas City School District ordered a mass evacuation of all schools within a few miles of the Bottoms, including Scarritt, McCoy, Gladstone, Garfield, Whittier, Trailwoods, Woodland and James elementary schools. Students were transported to the Paseo Academy High School at 4747 Flora Ave. Parents with questions can call 816-418-7549, 816-418-7565 or 816-418-7610.

The Kansas City School District said students and staff members were told not to walk home.

KMBC's Martin Augustine reported that thousands of students were bused to Paseo, and that teachers helped keep the children calm.

"The teachers were magnificent," Superintendent Anthony Amato said.

Kansas City Southern Railway Co. shut down its rail yard operation near the plant and evacuated workers as a precaution.

KMBC's Micheal Mahoney reported that parts of the city's emergency evacuation plan were put into use Wednesday. The plan was developed last year as part of a homeland security policy.

Kansas City Emergency Management Director D.A. Christian said there are three levels of evacuation, with 1 being the lowest and 3 being the highest.

"We were at Level 3, and now we're at Level 2," Christian said Thursday evening.

He said this was the first Level 3 evacuation during his three years in Kansas City.

"We'll look at how the evacuations went and find ways to do it better," Christian said.

Crews To Let Fire Burn Itself Out

Dyer said crews are not fighting the fire with water because the runoff would cause an environmental problem of potentially hazardous materials.

"We are not fighting this fire at all," Dyer said. "The only way to handle this fire is to allow it to burn itself out."

Dyer said one fire truck crew briefly used a water stream on the blaze, but they were told to evacuate.

"It was definitely a fire that could not be extinguished, it could not be controlled. It was essential to pull back -- this could have killed firefighters," Dyer said.

Several fire trucks, ambulances and a hazardous materials crew are on standby.

"It's been an outstanding response, and I couldn't be more proud of our personnel at the scene," Dyer said.

Dyer said the best-case scenario is that the fire will burn out by Thursday morning and the worst-case scenario is that the fire will burn for 72 hours.

The fire chief said he expects to use a new foam tanker to fight the fire. The tanker was purchased using a Homeland Security fund.

KMBC reported that Chemcentral had a fire at its Seattle plant in 1999 and it took 12 hours for the fire to extinguish.

Debris Falls From Smoke Plume

A huge plume of smoke could be seen coming from the Chemcentral building Wednesday afternoon. The dark cloud was visible for at least 30 miles and winds had blown the smoke to other parts of the metro area, KMBC reported. Viewers in Lawrence, Kan., said the smoke had drifted to their area by late afternoon.

One viewer said "it looked like a towering tornado of black smoke."

Fire officials told residents throughout the city to avoid picking up debris carried by the dark cloud that streamed out of downtown, although Dyer said the material was not highly toxic. The cloud appeared to be dropping a sticky substance as it moved to the southwest. Dyer said it was unlikely that anything falling was dangerous, but officials urged caution anyway.

KMBC's Karen Kornacki said she saw some debris that was the size of a shoebox fall from the sky.

Officials said they believe the debris is material from the building that burned, and that an updraft lifted the material up into the air.

Rowlands reported that aviation officials have been warned about the plume of smoke and the falling debris.

Authorities said the smoke will not affect the city's water supply.

Buildings Shook, Lights Flickered

Workers in nearby buildings told KMBC they heard about eight explosions, the building shook and that the lights flickered. Viewers from across the metro area have said they heard the explosions and that their lights and TV flickered.

"I was just down off Front Street visiting a company we do some work for, and we heard some booms and looked up in the sky and saw some smoke. We decided to get out of there," said Jordan Smith, who was in the area at the time. "The electricity was going in and out. It kind of looked like it was power surges. We couldn't figure out what was going on and then looked up in the sky and found out something was on fire."

"I heard quite a few explosions. We actually felt the explosions. The whole house shook while we were inside. I was actually getting here from work, and we felt the whole house shake," said Francisco Munos.

Several hundred residents lost power for a few hours because of the explosion, but utility crews said most of the customers had their power turned back on by Thursday night.

Chemical Testing Under Way

Thje Environmental Protection Agency is monitoring the situation and officials said no ground pollutants have been found in downtown Kansas City, but they asked people not to come to the scene.

"We just don't know what's up there at this point," EPA spokeswoman Kim Olson said.

Officials said they are not seeing a declining quality in the city's air.

Wednesday evening, the EPA used a plane to fly through the smoke plume to get an air sample that could be tested for toxic chemicals.

"Until we have measurements from the EPA, we can't tell you exactly what that air is. But smoke is never a good thing to inhale," said Dr. Rex Archer, director of the Kansas City Health Department.

Health officials advised those with asthma or respiratory problems to stay inside, to take their medicines or to check with their doctor.

Ken Hannon, a spokesman for the Missouri Department of Natural Resources, said a number of chemicals are at Chemcentral, including mineral spirits, turpentine and other solvents.

"I'm looking through the list. I'm not seeing anything that's jumping out at me" as particularly hazardous, he said. "Flammability seems to be the main concern right now for most of these chemicals."

"They have roughly the same characteristics of diesel, kerosene, gasoline and so forth, as far as their burning characteristics. None of these have a high rating for toxicity," Dyer said.

Plant Has 'Good Safety Record'

Chemcentral is based in the Chicago suburb of Bedford Park. Dan Brennan, an attorney at Chemcentral's headquarters in Bedford Park, Ill., said the Kansas City plant has 15 to 20 workers.

Dyer said the Chemcentral facility did not have a history of problems, but it is a location that has always troubled the fire department because of its proximity to a casino and residential neighborhoods.

"It's a well-run facility with a pretty darn good safety record," he said. "When you ask if it's something that comes up as a problem facility -- absolutely not."

"Fifty some years and not a problem," Nienhueser said of the facility.