The Prince George's County Fire Department reported this week that nearly half the emergency trips made by county ambulances -- or about 20,000 calls each year -- are unnecessary.

At a press conference, county Fire Chief M. H. (Jim) Stepp said that the unnecessary calls included those for persons using ambulances for such ailments as toothaches and colds, or for doctor's appointments. The unnecessary calls tied up ambulances needed for genuine emergencies, he said.

One spokesman said ambulances were being used as a "taxi service."

The county now uses about 40 ambulances, operated by 330 county firemen and 650 volunteers trained as emergency medical technicians. Estepp said the extra cost to the county for each unnecessary ambulance trip is approximately $75 to $100.

He described one incident in which a woman called for an ambulance. On the way to the hospital, the ambulance crew noticed that her condition seemed to improve quickly. It turned out that she was meeting a date at the hospital.

"Some people who call underestimate the need or misunderstand the purpose of the county's ambulances," said another fire department official.

Estepp said that because of the heavy overuse of ambulances -- some of which make 2,000 to 3,000 calls a year -- the fire department would take action to curb unnecessary calls.

Estepp said that some ambulance crews may inform patients that they do not need ambulance service, and will suggest another means of transportation to the hospital.

Estepp also said the fire department wanted a new policy to take into account how far the hospital was from an ambulance call, to avoid keeping an ambulance out of service for a long time.

The department said it would expand its public education program to supply information to county residents as to the proper use of ambulances.