A tanker truck overturned on a ramp entering the Capital Beltway from I-95 in Prince George's County yesterday morning, spewing about 50 gallons of a toxic chemical onto the icy ground, closing several interstate ramps, and creating a massive all-day traffic jam that dampened the spirits of many holiday motorists.

The driver of the tanker, Cedric Fryar, 30, of Clinton, received minor cuts and bruises and was treated at Prince George's General Hospital and released, according to Maryland State Police. Fryar later was charged with driving faster than the 30 mph speed limit for the ramp.

Tony DeStefano, a spokesman for the Prince George's County Fire Department, said Fryar was transporting 45,000 pounds or almost 4,000 gallons of ferric chloride from Baltimore to the Blue Plains sewage treatment plant in the District. The chemical, although not flammable, is highly corrosive and can burn the eyes, nose, throat and lungs. It is used to treat waste.

DeStefano said residents near the accident site were never in any danger from the spill. "The 50 gallons that spilled were contained in a ditch," and the nearest residential community -- White Oak Manor -- was more than 4,000 feet away, he said.

The Beltway was the scene of several truck accidents last summer, including one in Prince George's in which a tanker truck carrying 1,600 gallons of propane fuel turned over and caught fire in September, leading to the evacuation of hundreds of residents near the accident site. Prince George's County firefighters let the propane burn itself out, fearing that the truck would explode if they tried to douse the fire.

Between July 1983 and June 1984, there were 340 accidents on the Beltway involving trucks, according to the American Automobile Association.

Several jurisdictions have attempted to put restrictions on trucks' using the Beltway.

Fairfax County has endorsed the concept of an outer Beltway from I-270 near Frederick, Md. to I-95 north of Fredericksburg, Va., diverting much of the tractor-trailer traffic from the Beltway. Also, the county has asked for stricter federal inspection of trucks carrying hazardous materials.

After yesterday's accident, which occurred about 8:40 a.m., a two-mile portion of I-95 south of Beltsville was closed for several hours.

The highway was reopened later in the morning, but two ramps from I-95 to the Beltway remained closed for most of the day while firefighters worked to clean up the spill and transfer the chemical remaining in the overturned tanker to another truck. The process was completed by about 6 p.m.

The Prince George's County Fire Department's Hazardous Materials Response Team, a group of volunteer firefighters who use state-of-the-art technology to clean up chemical spills, was on the scene within four minutes of the accident, said DeStefano.

The team mobilized quickly. Members scurried about dressed in gray rubber body suits, rubber gloves and boots. They set up a roped-off decontamination area with chemicals and large metal tins for washing off the dangerous chemical.

On the ground nearby were dozens of air pumps and masks.

While waiting for a dump truck and pump truck to arrive to begin the cleanup, some firefighters munched on Big Macs and sipped coffee from plastic cups. Others huddled near kerosene heaters to keep warm in the biting cold.

The team took color pictures of the overturned tanker and closeups of a vent pipe buried in the mud that was the source of the spill. They developed them in about hour and used a microfiche machine in a special truck to look at the pictures.

Also at hand were hundreds of maps of water and sewer pipes just in case the spill worsened and began to threaten the ground water.

In a special truck, John Hess, a member of the response team, sat in front of an IBM computer, listening to radio messages and keeping a log of every development.

The log was printed out continuously and given to team members to keep them updated on what everyone else on the team was doing. The team will review the log after the spill has been contained to critique its handling of the emergency. Explained Hess: "There is a potential for disaster here and it's important to step back and evaluate how we made decisions, to see where we went wrong and where we went right."