On June 25, 1989, several junior volunteer firefighters were sitting around the District Heights Fire Station and complaining that no one, least of all the chief, took them seriously.

As 16- and 17-year-old youths, they were thrilled at the chance to ride the fire engines they had admired since they were small boys. Yet they often felt stung by Volunteer Fire Chief Thomas Stommel's criticism of their performance.

On this evening, the conversation took a fateful turn. It was then, one of the volunteer firefighters since charged with arson said yesterday, that the notion to set fires in vacant houses was born.

"Before the fire, we were just sitting around bored. We were talking about how the chief yells at us for the things that we do wrong and everybody was saying, 'Let's wait for the next fire to come out and maybe we can do good on it,'" said Robert W. Vasquez, 18, who was charged with arson on Wednesday. "And then the words, 'Set a fire' came up."

Vasquez said that he told his friends that he thought it was wrong to start a fire. But he ultimately agreed to ride along with them and watch because, he said, "I figured that if I was going to have to fight it, I wanted to know what I was up against."

"I did not go in and do it," Vasquez said. "I was there. I sat in the car across the street, but I did not go in and do it."

Prince George's County fire investigators charged 11 volunteers from the District Heights and Boulevard Heights companies this week with burning 10 vacant houses over the last year, allegedly for the fun of extinguishing the fires. A diary in which one of the volunteers detailed the times and locations of a few of the fires led investigators, who for months had suspected an arsonist at work in District Heights, to members of their own department.

The diary's owner, who also was charged with arson, later implicated other volunteers, who in turn gave investigators more names, fire officials said. The diary, according to a charging document, told of three failed attempts to set a fire in a house on Ritchie Road in District Heights before a successful blaze was started on July 26 in a vacant building in the 7600 block of Marlboro Pike.

Fire officials said that the arsons, which occurred between June 1989 and last July, were not done for money. Most of the houses were vacant and had been deemed uninhabitable before the blazes; two or three houses were insured, fire officials said.

Also charged with arson were Rodney Jerome Hall, 20, Demetrius Terry, 18, Napoleon L. Queen, 21, and Kenneth Armstrong, 22. Six of those charged were 17-year-old juveniles.

Fire Chief Steven T. Edwards denounced the arson as the "worst crime a firefighter could commit." Fire officials said most of the volunteers charged gave statements acknowledging their roles in the fires. Vasquez said he told investigators that he saw the Walker Mill fire but did not start it.

The groups from District Heights and Boulevard Heights apparently acted independently of each other and had only heard rumors of the other's involvement, fire officials said. The incidents, while rare, are not unprecedented among volunteer firefighters. Fire officials said the motive of both groups -- where one could be determined -- was to generate fires that would enable them to show off their firefighting expertise.

Such was the case on June 25, 1989, Vasquez said. Vasquez has been charged with one count of arson stemming from a fire in a vacant house in the 6600 block of Walker Mill Road. He said he was not involved in any of the other fires.

"It was just a big hassle trying to prove yourself to the chief," said Vasquez. "It was like everything that ever happened was blamed on us . . . . They felt like if they had more fires they could prove themselves to the chief."

The next day, Vasquez said, Stommel complimented the junior firefighters on their work at the Walker Mill Road fire.

"He congratulated us on the way the fire got put under control pretty quickly," Vasquez said. "I was happy. I felt like I had done something right, as far as fighting the fire was concerned."

Stommel declined to comment. Edwards called Stommel one of the most experienced and respected volunteer chiefs in the county and credited his administration at the District Heights station with bringing the problem to the department's attention.

Vasquez said that he was surprised and somewhat frightened by the speed with which the blaze in the house on Walker Mill grew. The fire, which in the beginning was just an orange glow seen through the windows of the vacant house, had become a bonfire by the time the fire truck arrived about five minutes later, Vasquez said.

"They got back in the car and we drove back to the station," Vasquez said. "It didn't look that big when we left, but when we got back there on the truck, the whole house was on fire."

Vasquez said that firefighters had to wear breathing apparatus to fight the fire, which ultimately was extinguished without injuries.

Vasquez, who left high school after the 10th grade, worked for the District Heights Public Works Department until his arrest this week, when he was suspended. Like the other volunteers, Vasquez said, he was required to sleep at the station two nights a month but often spent much of his free time there.

He said he had wanted to be a firefighter since he was 10 years old and first admired an engine at the District Heights station.

"It isn't like we wanted to go out and burn down houses to hurt people," said Vasquez. "The firehouse was like our second home, and we were just tired of getting hassled and never having anybody say nothing good about what we did."