The tobacco industry has accused GAF Corp., once a major producer of asbestos, of resorting to a "ploy" to impede prosecution and settlement of product-safety cases brought by asbestos workers who blame their lung diseases to on-the-job exposures to the mineral.

American Brands, Brown & Williamson, Liggett Group, Philip Morris, and R. J. Reynolds made the accusation in papers filed in California state trial courts in San Francisco, Alameda and Solano counties. The tobacco companies argue that they should not be made codefendants in the litigation as GAF has proposed.

American Brands, the first of the companies to respond to the GAF move, emphasized that the workers "did not sue the tobacco companies; they sued the asbestos companies." In addition, American charged, GAF has confronted the cigarette makers "with issues of fundamental fairness and due process of law," particularly in the context of seven cases set for trial this month.

American has asked Superior Court Judge John E. Benson in San Francisco to dismiss the tobacco industry from the 161 cases pending before him, and he has set a hearing for Dec. 13.

GAF is the defendant in a total of 276 pending asbestos lawsuits in the three courts, and, as of March 1, in more than 18,000 elsewhere. The company is a Wayne, N.J., producer of building materials and chemicals.