Their posture was erect and smiles played at the corners of their mouths as Kim I. Mattox and Laura B. Samuel walked stiffly across the front of the room to receive their graduation certificates and become the second and third women firefighters to join the D.C. Fire Department.

For Mattox, 22, the achievement was another chapter in her already active career as a volunteer firefighter in Prince George's County. For Samuel, 28, the graduation last week was the winning round in a sex discrimination battle that nearly resulted in her expulsion from the fire academy last fall.

Graduating along with the women were eight male classmates, who encouraged them throughout the 10-week training session, Samuel and Mattox said. The two women join Beatrice Rudder, 25, who a year ago became the first woman to join the District fire department.

Top academic honors went to Reginald N. Johnson, an agile, long-legged firefighter better known to students and instructors as "Silky" Johnson. Awards for physical agility were shared by Johnson and firefighter Kevin Ortiz. And Mattox was honored for the best academic performance in an 81-hour medical training course.

The short graduation ceremony was followed by a fire academy-produced training film starring the graduates. As relatives looked on anxiously, the 10 men and women deftly scaled tall buildings, battled blazes, and fought stubborn, smoke-belching chemical fires.

For some of the graduates, like former Montgomery County firefighter Kevin Ortiz, the training session provided more action then past experiences.

"I didn't make any runs in Montgomery County. I slept all the time," said Ortiz, 21, explaining why he applied to the D.C. Fire Department.

Mattox, who is assigned to a station in the Shaw area, said she expects to see plenty of action at the station, which is located "in the middle of everything." She said she decided to take the entrance exam two years ago and was encouraged by her family and fellow firefighters.

"Firefighting is something I want to do for a long time to come," she said.

Samuel said the challenge of the job and the promise of upward mobility encouraged her to move form supermarket cashier to firefighter. Yet for the woman affectionately known to her classmates as "Sam," becoming a firefighter presented more of a challenge than she expected.

Last October, Samuel faced expulsion from the fire academy for poor academic performance. She charged that her poor performance resulted from harrassment by academy instructors who were sexually biased. Samuel took her complaint to the fire department's Equal Employment Opportunity officer, who decided she had been "subjected to undue stress because of her sex," and was required to perform physical exercises "that had not been required of previous trainees."

Samuel's allegations were upheld by the city Human Rights Office and former City Administrator Julian Dugas. The fire department was ordered to reinstate Samuel in the academy, without penalty, last Feburary.

Her certificate in hand, Samuel said she wants to forget her first experience with the department: "That was more or less resolved."

She prefers to compare the two classes by recalling, with fondness, the helpful instructors and students from graduating class 272.

"For one thing it was a hell of a lot better because there was another woman here," she said. "I don't think one woman should come through (training alone). It's nice to have at least one, maybe two women."

The class of 10 students was also smaller than her first class, which included 23 men, Samuel said.

"It seemed like a close knit group. You got to know everybody a little better and there was more individual instruction" she said of her graduating class. "(Instructor) Sgt. Shelton Arthur was very helpful. In fact, all of them were."

Despite her negative experience, Samuel said she would encourage other women to become firefighters.

"It's a new field and there are going to be tough times. But it's like that when women go into any new field," she said.

Graduating along with Mattox and Samuel were firefighters Gary Charles Danley, Anthony S. Dimuzio, Frederick J. Heller, Reginald N. Johnson, Kevin F. Ortiz, Louis P. Prather Jr., John M. Spadaro and Anthony Stuckey. CAPTION: Picture, New graduates of the D.C. Fire Department's Training Course, Kim Mattox, left, and Laura Samuel. By Michael Ford Parks-The Washington Post