Officials of the Firestone Tire and RubberCo. told a House subcommittee yesterday that a proposed recall of [WORD ILLEGIBLE] Firestone 500 steel-belted radial tires, which could cost the company upto $300 million, "is unjustified."

But the growing controversy over possible safety defects in the tire was fueled by the testimony of two other witnesses, a former Firestone sales official and a West Virginia motorist who walked into the hearings at the last minute, rolling before him the remains of a Firestone 500 that blew out while he was driving to Ohio last week.

The hearing by the Subcommittee on Oversight and Investigations followed by only one day the announcement by the National Highway Traffic Safety Administration that the government found the tire to be defective. The agency has proposed the recall of the 13 to 15 million 500's still on the road.

In his opening remarks, subcommittee chairman John Moss (D-Calif.) cited 514 letters received from consumers in less than a month complaining about problems with the tire.

"The decision to resume these hearings (which began last month) rests on the subcommittee's deepening concernover potentially serious safety [WORD ILLEGIBLE] posed to persons still driving on Firestone 500 Steel-belted Radials," Moss said.

Firestone's director of Trade Sales, Thomas Mertz, and Vice President, Secretary and General Counsel John Floberg defended the company and the tire in their testimony.

Mertz said that much of the reason Firestone tires were generating an abnormally high number of complaints was "because our name has been in the paper constantly."

Mertz said that there had never been internal discussion within Firestone that the tire was defective and should be recalled, even though consumer complaint figures were running high on the 500.

But that testimony was contradicted by Edward Stocker, a Firestone sales official on the West Coast. For the past eight years, Stocker, owned a Modesto, Calif, tire dealership that sells Firestosne tires.

Stocker, who was subpoenaed to appear by the subcommittee, said he flew to Akron, Ohio in April, 1976, to personally meet with Firestone officials and warn them about major problems he was having with returns from consumers on the 500.

"I first alerted Firestone in 1975," Stocker said. He said he told the Firestone District manager then that the rate of tires being returned had jumped from 3 percent to 13.5 percent. "His reaction was that it was a local condidion," Stocker said, pointing out that his dealership is located in an extremely hot region.

Firestone officials told Stockerthat new versions of the Firestone 500 would solve the problem, but "they did not," Stocker said. Then Stocker said, he contacted Mertz about the same problem in July, 1977. Mertz said he didn't rememeber talking about safety problems.

Asked if he thought the tire which was discontinued last year, should be recalled, Stocker said he had nothing to add to the NHTSA determination that it should.

Following Stocker was surprise witness Robert D. Doyle, a Martinsburg, W. Va., motorist who said that one of his Firestone 500 tires blew out while he was driving to Columbus, Ohio last week.

After rolling in the tire and placing it on the witness table, Dolye told how the tire blew out while he was passing another car in his 1976 Mercury, with "only 15,000 miles on it."

Dolye said he went to his local Firestone dealer, who measured tread wear on the tire and offered him a new tire at a 22 percent discount, but nothing more. Dolye said he also submitted two estimates for damage to his car, caused by the blowout for the sums of $220 and $249, but did not know if Firestone would pay the damage.

Dolye said that after reading news accounts of the NHTSA announcement on Sunday, and finding out that "Mrs. Dolye's brother in Columbus also had trouble with his Firestone tires," he decided to drive to Washington for yesterday's hearings.

"I don't take these things lying down," he said. "I am fearful of driving on these tires, and Mrs Doyle is fearful of them, too.

Firestone's Floberg assured Dolye that the company had a mechanism for dealing with such problems, and guaranteed him that he would be reimbursed.

Moss' staff introuduced other letters from concerned motorists recounting their problems with the Firestone 500. One letter, from Fort Myers, Fla., attorney Douglas Waldorf said that two of his 500's blew out "while the car was at rest" in his garage.

"Since I bought my 1974 Ford LTD station wagon 3 1/2 years ago," wrote Clifford Smith of Rochester, N.Y., "I've had nothing but problems - big ones."

Pointing out that his car had Firestone 500's as original equipment (many cars do), Smith said he had experienced six blowouts, and that one narrowly missed harming his family and himself.