The U.S. Department of Agriculture on Monday designated Somervell and 212 Texas counties as primary natural disaster areas, saying they have suffered "one of the worst droughts in more than a century."

The announcement came as Dwayne Griffin, the county's emergency management coordinator and fire marshal, the Texas Forest Service and the Texas Department of Public Safety urged residents to use extra caution and avoid any activities that could generate a spark and ignite a wildfire.

Somervell County continues to have a burn ban in force. In addition, fireworks are banned (with the exception of the professional show being staged at Wheeler Branch Reservoir).

Griffin said law enforcement officers will be on the lookout for violators of the bans.

"On Saturday, Sunday and Monday, we'll be particularly looking for violators from fireworks," Griffin said.

He plans to be present when the fireworks show takes place at Wheeler Branch Reservoir Sunday night. Three fire trucks and tankers also will be there on standby, he said.

About 90 percent of all Texas wildfires are caused by human activity, according to the Texas Forest Service. Burning debris and sparks or burning trash blown into the air are the No. 1 cause of fires, the service added.

But any activity that might generate a spark mowing a lawn, riding a four-wheeler, parking a running car in the grass or even baling hay also pose dangers.

Recently, a fire broke out when a man on a tractor was cutting his hayfield and the blade hit a rock, generating a spark, Griffin said.

"It's very, very dry and it's just going to get worse," he added.

The USDA designation came after the drought, wildfires and other natural disasters caused losses of 30 percent or more of forage crops, pasture, corn, oats and wheat.

"Many producers have lost their crops due to the devastation caused by the drought and wildfires," said Agriculture Secretary Tom Vilsack in a statement. "President Obama and I want these farmers and ranchers to know that we will support them through the recovery process and help them once again become productive suppliers of food, fiber and fuel that keep America prospering. This designation will help provide that support."

Farmers and ranchers in Somervell and the other counties are eligible for low-interest emergency loans from USDA's Farm Service Agency, provided eligibility requirements are met. They have eight months from Monday's declaration to apply for loans. For more information, see the Web site at disaster.fsa.usda.gov.

The DPS also urged Texans to avoid situations that could ignite wildfires. Steven C. McCraw, the department's director, asked all cities, counties and families to cancel fireworks plans for this July 4 weekend.

"It's just too dry, and our firefighting resources are stretched too thin to be able to cope with potentially massive outbreaks of fires caused by fireworks," McCraw said.

As of June 19, more than three million acres have burned in Texas since the fire season began in December.

"Those 10,848 fires had a fiscal impact of more than $116 million in damage," according to the DPS. A volunteer firefighter from Cactus and one in Eastland died in April while fighting fires.

Wildfires have destroyed more than 500 homes, but more than 16,000 homes were saved.

Follow these rules to help prevent fires, the DPS says:

*Watch out when pulling off a road or driving into a field because hot catalytic converters can ignite dry grass.

* Don't burn trash, even in a barrel with a screen. Sparks can escape.

*If you smoke in your car, use an ashtray for extinguishing cigarettes. One of the fires that began in Palo Pinto County likely was caused by a burning cigarette, authorities said.

*Keep a fire extinguisher and water near by when outside working with equipment that gets hot. Water down outdoor work areas if you can.

To learn more about how to protect your home or ranch, visit the DPS Web site at www.txdps.state.tx.us or agrilife.tamu.edu/drought.