The same firm found last week to have used improper testing techniques in the government-sponsored safety investigation of the Ford Maverick also performed the major testing that led to the massive recall of the Ford Pinto, the Washington Post has learned.

Phoenix-based Dynamic Science improperly used cars that had already been involved in major accidents when it tested the Ford Maverick and Mercury Comet for fuel system leaks during crashes, according to the National Highway Traffic Safety Administration.

Last week, NHTSA withdrew its initial determination that the 1970-73 Mavericks and 1971-73 Comets had safety defects, after discovering that at least two of the six cars tested had been in previous accidents.

At that time NHTSA administrator Joan Claybrook wrote Ford Motor Co. that the fuel systems in the tested vehicles might not have been in their original configuration because of the previous accidents. She said this undermined the initial determination that the cars were prone to fires in rear-end collisions.

Ford discovered that Dynamic Science - which is one of the largest auto testing firms in the country - had used previously crashed cars when NHTSA gave the automaker the supporting documentation for its safety-defect determination. Ford engineers investigated the cars that had been crashed and found the markings of the earlier accidents.

Yesterday, NHTSA officials confirmed that Dynamic Science's only other testing contract involving an alleged auto safety defect was for the Ford Pinto. Crash tests of the Ford Pinto led to a negotiated recall of more than a million cars, the largest auto recall in history.

Dynamic Science was paid $186,000 last year for its crash tests of the Pinto and the General Motors' Chevrolet Vega (part of the same investigation) and another $61,000 for similar tests on the Maverick and Comet, NHTSA acknowledged yesterday.

The testing firm has received over $1.6 million from NHTSA for a variety of tests over the past two years, including crash tests of research vehicles. But the Pinto and Maverick cases were the company's only tests for safety defects.

Dynamic Science Testing Director Bert Enserink declined to comment on either investigation, referring calls to NHTSA.

One NHTSA spokesman said the agency was "looking into the previous tests performed by the company, including the Pinto tests, in light of the Maverick problem."

Ford had no comment on the situation.