The controversial Firestone Tire & Rubber Co. 500 steel-belted radial is a safe and reliable tire "comparable in every essential respect with the first generation steel-belted radial tires of other manufacturers," company spokesmen told government hearings yesterday.

But at the same time, federal safety officials released previously confidential, correspondence sent from Montgomery Ward to Firestone nearly two years ago, complaining that identical Firestone-made tires sold by Wards were causing consumer problems "of epidemic proportions."

The letters between the tire company and the huge retailer reveal that Firestone paid Montgomery Ward an extraordinary $500,000 payment ind-January 1977 "for excessive tire adjustments."

But most of the morning session of yesterday's second day of hearings held by the National Highway Traffic Safety Administration was devoted to Firestone's counterattack against NHTSA's attempt to force the tire company to recall an estimated 13 million of the steel-belted radials still on the road.

NHTSA called on Firestone to recall the tires last month, when the safety agency made an "initial determination that a safety-related defect exists in Firestone under other brand names."

Firestone made an estimated 8.3 million such tires for Montgomery Ward, Shell Oil Co., and others, with an estimated 5.5 million of those tires still on the road. It is unclear how those tires would be affected by the proposed recall.

Yesterday, Firestone attorney Pattrick McCartan spent an hour delivering the company's statement protesting the NHTSA determination. He sharply criticized the data NHTSA used to reach its conclusions, claiming that the agency was not relying on scientific data, but instead using consumer complaint data he said was unsubstantiated.

"The Firestone Steel Belted Radial 500, which the NHTSA . . . claims has some unspecified safety-related defest, has provided motorists more than 660 billion miles of service," McCartan said.

"Nowhere in the investigative report which accompanied the initial determination does the NHTSA's Office of Defects Investigation identity, or even suggest, the existence of any safety-related defect in either design or manufacture of the Steel Belted Radial 500 tire," he added.

McCartan said that the tire complied with Federal Motor Vehicle Safety Standard No. 109, "which represents the criteria established by the NHTSA for the highway safety of tires.

"(That) should be conclusive evidence that the tire contains no safety-related defect of the kind now sought to be established through what is claimed to be a comparison with the performance of other tires of similar construction," he said.

NHTSA said it made its initial determination on July 9, after reviewing 6,000 consumer reports alleging more than 14,000 individual tire failures, 29 deaths, more than 50 injuries and hundreds of accidents involving property damage.

The agency also said that the Firestone 500 had by far the highest rate of adjustment of the tires made by six domestic firms it surveyed.

But McCartan called adjustment figures misleading because comparisons with other tire companies do not reflect the fact that Firestone has a "liberal adjustment policy". And, he said, consumer complaints over Firestone 500s were abnormally high because negative press reports about the tire encouraged people to file such complaints.

"Conspicuously absent from the investigative report is any comparative scientific evaluation of the design, construction or performance characteristics of the 500 in comparison with radial tires of other manufacturers," McCartan said.

"And no effort appears to have been made by the NHTSA to obtain, analyze, or to compare consumer complaints, claims, or accidents relating to other tires, even though the agency's conclusions concerning the Steel Belted Radial 500 are said to be supported by comparative data of this kind," he added.

McCartan said that NHTSA withheld from the company information that the agency used in making its determination. "That's not true," said NHTSA Adminstrator Joan Claybrook in an interview after Firestone's testimony. "Everything was available to them here."

McCartan also attacked some of the testimony given the first day of hearings on Monday, which another Firestone official labeled a "circus". He showed closeup photos of three different tires that consumers testified on Monday had failed on their vehicles.

In one of the tires, the photos showed that the tire had been plugged earlier "to remedy a severe puncture. The presence of the puncturing object and the soft plug permitted excessive amounts of moisure to collect in the tire over a long period of time," he contended.

In another case, Firestone photos of two tires disputed claims by Deborah Federick that they had failed. A closeup photo of one tire shows it probably had been damaged in mounting, "causing the tire to lose air and to be run in an underinflated condition," McCartan said. Firestone long has maintained that underinflation leads to tire failures.

Photos of the second tire revealed "a 1 3/4-inch nail in the crown of the tire at the time of the failure, which was still in the tire when it was examined," he said.

McCartan said Firestone has not been permitted to examine the tire involved in the South Carolina Clement case, which resulted in three deaths and the amputation of the right leg of a seven-year-old girl. "But the investigating officer's description of the accident raises a serious question as to whether a tread separation initiated the accident," he said.

In a related statement yesterday, Rep. John Moss (D-Calif.), chairman of the House oversight and investigations subcommittee, which held hearings on the Firestone tires, wrote NHTSA to say that his staff has received 1,147 letters from the public discussing problems with radial tires, and that 834 of the letters concerned Firestone.

Discounting Firestone's claim that its tires are as good as any others made, and that consumer problems resulted from underinflation, Moss said, "There is no way that one company could corner all of the underinflators in the nation and have those underinflators primarily use its 500 steel-belted radial.