A massive explosion at a fertilizer plant ripped through a small Texas town, creating a powerful shock wave that flattened homes, smashed windows and could be felt as far as 80 miles away.

The explosion at the West Fertilizer Co. in the town of West exploded Wednesday night after the plant caught fire.

In a phone interview with NBC News on Thursday, West Mayor Tommy Muska said there are "30 to 40 missing people," including five firefighters. Muska said one fatality had been confirmed, but he could not say if it was a firefighter.

Muska told NBC News it's possible some of the missing "could be in a hospital, but the death toll "figure will be in that area" of 30 to 40.

The blast injured more than 160 people.

"[There was] just fire everywhere -- bodies on the ground, bloody bodies, people in panic," witness Sammy Chavez said. " Firemen, firetrucks, police cars filled the town."

Volunteer firemen from the West Fire Department initially responded to a fire at 7:30 p.m. at West Fertilizer Company. Six volunteer firemen responded to the fire, recognized the potential for an explosion and began evacuating nearby homes and businesses, Waco police Sgt. William Patrick Swanton said.

At about 7:53 p.m., the explosion ripped through the plant.

"We need your prayers," Muska said late Wednesday night. "There's a lot of people that got hurt. There's a lot of people, I'm sure, will not be here tomorrow."

First responders worked through the night to evacuate residents and conduct door-to-door welfare checks on residents in the blast area.

Witnesses said several nearby buildings -- including a high school, a nursing home and an apartment building -- were severely damaged.

The nursing home's 133 residents were safely evacuated, officials said.

Swanton said on Thursday morning that a significant area near the facility had been flattened and that "part of that community is gone."

Gov. Rick Perry declared McLennan County a disaster area, saying it's been a "tragic, difficult 16 hours for all of us."

Through the night, firefighters struggled to contain the blaze because of toxic fumes. Officials were worried about an unexploded tank that continued to vent gas but said by Thursday morning that they were no longer worried about another explosion while the fire continued to smolder.

Watch video from Chopper 5 over West in the video player above.

Injured transported to hospitals in DFW, Waco, Temple

Late Wednesday, Texas Department of Public Safety spokesman Trooper D.L. Wilson said more than 100 people were injured. According to hospital counts by early Thursday morning, at least 167 people were treated at hospitals in Waco, Temple, Dallas and Fort Worth.

Hillcrest Baptist Medical Center in Waco treated more than 100 patients, three of which remain in critical condition, the hospital said Thursday morning.

More than 50 people were treated and released by emergency medical staff, but 28 were admitted to the hospital and another five were admitted to the intensive care unit.

Hillcrest Baptist reported no fatalities and said five surgeries were performed on blast victims. Some patients needed fertilizer decontamination, including irrigation of the eyes.

The hospital, a Level 2 trauma center, said it was still on standby to receive more patients if needed.

Providence Hospital, also in Waco, received 65 patients.

Parkland Memorial Hospital in Dallas confirmed that it was treating two people injured in the West explosion. One arrived by helicopter, and other was transported by ambulance, the hospital said.

John Peter Smith Hospital in Fort Worth confirmed Wednesday night that one patient was sent their way.

Scott & White Memorial Hospital in Temple, a Level 1 trauma center, said it received three patients. Two children were transported to McLane's Children's Hospital, also in Temple.

The extent of their injuries was not immediately available. Word on the patients' conditions was expected to be released at some time Thursday.

Powerful blast registered as earthquake

The explosion occurred at about 7:50 p.m. while firefighters were at West Fertilizer Co. in the town of West in McLennan County. Firefighters responded to the plant after the fire was reported at the plant in the 1400 block of Jerry Mashek Drive at about 7 p.m.

According to the U.S. Geological Survey, the explosion at the fertilizer plant registered as a 2.1-magnitude earthquake.

The magnitude is "substantially less than the true size of the event" because the magnitude only measures the ground motion, not the air wave, the USGS said on its website.

West Mayor Tommy Muska, himself a firefighter, said the "very powerful explosion" occurred after he and other firefighters arrived at the scene. The plant was fully engulfed in fire before the explosion, he said.

Swanton said the West Fire Department responded to the fire, realized the volatility of the situation and began to evacuate nearby homes and businesses. About 50 minutes after firefighters arrived, the "massive explosion" occurred, he said.

Muska described the explosion as so powerful that it "blew my hat off" and blew the mirror off his vehicle.

"I felt it before I heard it," he said.

A resident who lives two blocks away from the plant told NBC 5's Ray Villeda that the impact felt like a plane had gone down near her.

West is about 70 miles south of the Dallas-Fort Worth area, but people as far north as south Arlington reported feeling the explosion. Numerous NBC 5 viewers in places such as Cleburne, Waxahachie and Midlothian contacted NBC 5, saying they believed they felt an earthquake.

Muska said he did not know how many homes were affected by the blast's five-block radius. His own home's windows and doors were blown off, he said.

Wilson said 50 to 75 homes were damaged, in addition to 50 units at an apartment complex that were just "a skeleton."

Swanton described the damage as "quite a bit of devastation" in the downtown area.

Viewers told NBC 5 that a nearby nursing home and an apartment complex sustained serious damage in the blast. Chopper 5 could see that the entire second floor of a two-story apartment building had collapsed.

Muska said 133 patients in a nearby nursing home were evacuated, most by wheelchair. The facility was in the process of being evacuated when the explosion hit, Swanton said.

The plant was still burning at 10 p.m., but Muska said at a news conference at 11 p.m. that the fire appeared to be under control.

At midnight, Wilson said that the fire was still smoldering. Fire crews could not get close to the facility because of toxic fumes, and the plant still had active ingredients, he said.

DPS said shortly after 1 a.m. that there was concern about an unexploded tank in the plant that was venting gas.

DPS, mayor: Town does not need more first responders at this time

The town of West has plenty of law enforcement and search-and-rescue crews on the scene, Muska said.

When asked what the town needs, he said, "We need your prayers. There's a lot of people that got hurt. There's a lot of people I'm sure will not be here tomorrow."

Wilson reiterated the mayor's request that no one come to West to help.

"We are overflowing with help, and we don't need any more help as far as that goes," Wilson said.

People can call the following emergency number for information on family and loved ones: 254-286-1100.

Door-to-door search for survivors

"About half" of the town had been evacuated, Wilson said early Thursday morning. Crews had cleared about an eight-to-10-block area and moved people back even further, he said.

Emergency responders went door-to-door to search for survivors, Muska said.

"We're going to search for everybody," he said. "We're going to make sure everyone's accounted for -- that's the most important thing right now."

Wilson said another house-by-house search was expected to continue all night long.

"We're worried about people right now, not property," he said. "We want people to be safe -- that's our main goal right now, is getting the people safe and getting them out of there."

People north of the plant are being asked to stay indoors because of concerns about the air quality.

Further evacuations could be ordered if the weather changes expected early Thursday morning change wind patterns, he said.

Winds in West would shift from the south to the northwest between 5 a.m. and 7 a.m. because of an approaching cold front, said NBC 5 meteorologist Samantha Davies.

Law enforcement said gas and power companies were turning off service in the area.

Police in West told NBC 5's Ray Villeda that looters were near the impact zone very soon after the blast. Security in the area was very tight early Thursday morning, he reported.

A triage scene at a nearby West High School was moved because of continued danger from the blast site. Dozens of firetrucks and ambulances moved blocks away from where they were staged at the football field.

All news helicopters were asked to leave the area at about 10:40 p.m.

The Federal Aviation Administration put a no-fly zone into effect three miles around West and below 3,000 feet. Only emergency aircraft will be allowed into the area.

Interstate 35 is closed in McLennan County because of the situation, creating major traffic backups along the highway.

The roads around the blast site are blocked off for emergency vehicles.

All West school district campuses will be closed Thursday and Friday. The district is asking that everyone stay away from school property in that time.

Future plans will be announced this weekend.

Gov. Rick Perry said Wednesday night that his office was monitoring the fire and gathering information.

"We have also mobilized state resources to help local authorities," he said in a statement. "Our thoughts and prayers are with the people of West and the first responders on the scene."

The U.S. Chemical Safety Board said it was deploying a large investigation team to West.

Swanton said he had no details on the number of people who work at the plant, which was cited by the Texas Commission on Environmental Quality in 2006 for failing to obtain or to qualify for a permit. The agency acted after receiving a complaint in June of that year of a strong ammonia smell.

How to help

As the tragedy unfolds, many have asked how they can help.

Officials said the following items are the ones most in need by victims: Diapers/wipes, new underwear, blankets, water bottles, gift cards for grocery stores or home supply stores, toiletries, sports drinks or powdered sports drinks, toilet paper, hand sanitizer, nonperishable food items, clothing of all sizes, bedding, dog and cat food.

Officials said Thursday they DO NOT need perishable items.

To find a location accepting donations for those in West, click here.

Watch NBC 5's Wednesday night coverage of explosion:

NBC 5 has crews on the scene and, as this story is developing, elements may change. NBC 5's Ben Russell, Omar Villafranca, Scott Gordon, Ray Villeda and Andres Gutierrez contributed to this report.