The Federal Emergency Management Agency is refusing to provide additional money to help rebuild the small Texas town where a deadly fertilizer plant explosion leveled numerous homes and a school, and killed 15 people.

According to a letter, FEMA said it reviewed the state’s appeal for help but decided that the explosion “is not of the severity and magnitude that warrants a major disaster declaration.”

FEMA already has provided millions of dollars in aid to the town of West and its residents, but the decision prevents them from getting some of the widespread assistance typically available to victims of tornadoes, hurricanes and other natural disasters.

It remains unclear what funds may not be available to individuals, but the decision likely means less money to pay for public repairs to roads, sewer lines, pipes and a school that was destroyed.

The blast killed 10 first responders and brought national attention to the agricultural community. President Barack Obama traveled to the area to attend a memorial service for the first responders and others who died trying to help.

As of Wednesday, FEMA said the agency and the U.S. Small Business Administration had approved more than $7 million in aid and low-interest loans to West residents impacted by the blast. FEMA also is paying 75 percent of the costs of debris removal and will reimburse the state and the municipality for the initial emergency response.

FEMA denied the “major disaster declaration” both for public assistance — which would give money to the city to help rebuild — and for further individual assistance.

It’s not unusual for FEMA to turn down that level of assistance for emergencies not stemming from natural disasters. In 2010, for example, officials denied a request for millions in aid after a gas pipeline explosion that consumed a Northern California neighborhood.

Some funds would be available in West through insurance pay outs and because it believes the state or the municipality has the resources to cover the costs, among other things, agency spokesman Dan Watson said in a statement.

Individuals can still receive rental assistance and some funds for rebuilding, and the state can appeal for more public assistance but some programs for individuals will not be made available, he said.

But West Mayor Tommy Muska said the rural community of 2,800 people cannot cover the costs of the repairs, and doesn’t believe that the state will provide enough money on its own. He estimated the cost of those repairs at about $57 million, including $40 million to rebuild schools that were destroyed or damaged when the West Fertilizer Co. blew up in April.

“We don’t have the money to go out and borrow the money. We don’t have the means to pay that note back,” Muska said. “There’s got to be some public assistance.”

The West Fertilizer Co. blew up after the plant caught fire, and the cause remains unclear. A criminal investigation is still open — but investigators say the heat of the fire destabilized tons of a potentially explosive fertilizer stored at the plant, leading to the massive blast that leveled chunks of the town. The incident highlighted how loosely regulated some chemicals are, including the ammonium nitrate that blew up, and has some critics saying the government needs to tighten its oversight of such plants.

The blast emitted a wave of energy so strong it registered as a small earthquake, knocked down people blocks away, blew out windows, left a massive 93-foot crater and curved walls of homes and buildings.