The Labor Department yesterday released its final version of a program to protect the hearing of an estimated 5.1 million workers employed in noisy places such as sawmills, foundries and automobile plants.

Thorne G. Auchter, head of the Occupational Safety and Health Administration, said the Reagan administration revised the program to save employers an estimated $81.4 million a year, while still "effectively protecting" workers.

Rules for the hearing program were promulgated in January, 1981, during the final hours of the Carter administration, but the most important and controversial provisions were put on hold immediately by the new administration.

The hearing program covers all workers, except those in construction and agriculture, who are exposed to an average noise level of 85 decibels or more during an eight-hour shift. It requires employers to monitor noise levels and give employes yearly hearing tests to determine whether their hearing has been impaired. The annual tests are to be compared with "baseline audiograms" that employers are required to give employes by March 1, 1984.

Mark A. de Bernardo, an official with the national Chamber of Commerce, said the chamber saw "significant improvement" over the Carter administration's rule, but that some of its members were disappointed that OSHA did not go further in several technical areas. De Bernardo said the chamber felt that biennial hearing tests would have been sufficient to monitor workers' hearing.

But Peg Seminario, an industrial hygienist with the AFL-CIO, had a different view.

"From the beginning, we have been seeking a standard that reduced noise in the work place. Unfortunately, in 1981, under the Carter administration, what we got was an ear-plug standard . . . . Now OSHA has given us a weaker ear-plug standard."

Auchter said a large portion of OSHA's savings--$23.2 million--would be achieved by allowing employers to monitor work-place noise with a fixed device rather than attaching monitors to each worker.

While fixed monitoring is cheaper, Seminario contended that it is less accurate than personal monitoring, which will be required only if OSHA decides that fixed monitoring is "inappropriate" in a particular case.