When Barbara Hackman Franklin leaves her post as a Consumer Product Safety Commission member next week, she will close one of the more significant chapters in the recent development of federal regulation.

Franklin is the last of the five original commissioners to leave the 6-year-old agency, which has been a model for many of the successes and the frustrations experienced by regulators in recent years.

"There has been a major thrust in government regulation in the last decade," Franklin said in a recent interview. "Before 1970, we didn't even have an Environmental Protection Agency, and Occupational Safety and Health Adminstration or a Consumer Product Safety Commission."

"And because of that rapid growth," she added, "there has been a lot of duplication and a number of overlap problems. Some of these problems are crushing small business, for example..."

But Franklin has seen major changes in the attitude of business consumers and the government toward regulation in general, and product safety specifically.

"What has changed is public sentiment toward regulation," she said, "which has colored the way the administration feels about things. You can tell by the different kinds of questions that are being asked today.

"And how the administration feels about regulation is crucial," she added, "because the decisions are still made here in Washington, and the tone in the city, the climate about government regulation, influences the kind of decision-making that goes on."

Six years ago, there was little talk about costs and benefits of government regulation, Franklin said or the impact of regulation on such things as inflation.

"I've always tried to make a costbenefit analysis part of my own evaluation of any proposed regulation," said Franklin, a Republican first appointed to the commission by Richard Nixon, after working for him in the White House as women's advocate.

"Although you can't be too specific about the benefits, such an analysis makes you ask better questions of your own staff," she said.

Franklin has an unusual background for a government regulator, being one of the first women to get a masters degree in business administration from Harvard.

That background, she said, has helped her understand the need for some cost-benefit evaluation in all regulatory proposals, and she is glad to see such evaluations being promoted by the White House's new Regulatory Council.

"Regulators have to be thinking more about where regulation is really needed," she said. "They must look for the best solution. The goal is to get the problem solved in the most efficient way."

Franklin said there is more "common sense" in regulation now than ever before. "Five years ago," she said, "industry would not be working with us the way they are now in developing safety standards for lawn mowers and chain saws, for example. Now, they know that we are here to stay, and we all want the same thing: safe products."

Business in general now places a higher regard on product safety even before the government enters the picture, Franklin said. "Business has changed," she said. "It's still not a perfect world, but the commitment is still not enough in many cases."

One of Franklin's highest priorities during her tenure has been trying to get the Carter administration to take a united stand in the area of cancer research, and to coordinate all activities aimed at reducing the carcinogenic dangers to the public.

While she is disappointed with the overall administration commitment, Franklin has been cheered by the work of an interagency group that drew upon four different federal agencies to coordinate their research data and make it easier for all four to go after carcinogens.

The 38-year-old Franklin will continue her work on the cancer problem in the future. It is likely that she will accept some form of a part-time professorship at Mt. Sinai School of Medicine's environmental science lab to continue studies of the effects of carcinogens and the government responsibilities in that area.

"Cancer is coming home to everyone, now," Franklin said."With talk about hamburgers and beer causing cancer, what is left?

The feisty administrator also may take a part-time position teaching at a well-known eastern business school, as well as positions on several profes sional and corporate boards or directors.

But mostly, Franklin wants to relax and spend some time in her native Pennsylvania, where she built a house with her husband. At least one of her board positions will be with a Pennsylvania bank holding company.

"I've had eight years in the government, starting with the White House," Franklin said. "And I am grateful for the opportunity to have served. I have learned and experienced a great deal. I'll miss having a direct involvement though."