Efforts to remove genetically modified (GM) food products from U.S. grocery shelves -- or at least to require mandatory labeling of such items -- continue to heat up. In March the Center for Food Safety, Washington, an environmental advocacy group, announced that it would petition the FDA to remove all GM food crops from the U.S. market pending a thorough examination of their effects on human health and the environment, and require mandatory labeling of foods comprised of at least 0.01% of GM content -- if they meet safety requirements. A Clinton administration plan announced earlier this month that would seemingly strengthen federal oversight of and increase consumer access to information about GM foods has not appeased anti-GM food critics. Among its components is a voluntary labeling measure. The Center for Food Safety's demands echo the content of several legislative measures introduced in Congress during the last six months. Major food-industry organizations, which say such action is unnecessary and could have far-reaching consequences for the entire agribusiness industry, are firing back with new ammunition of their own. They point to two studies -- one issued by the National Academy of Sciences and the other by a Congressional subcommittee -- released last month which they argue reinforce their position that genetically altered foods are safe. These recent events are merely the latest in an ongoing tug of war between factions on the GM issue in the U.S. Earlier this year three dozen trade organizations combined efforts in a letter sent to members of Congress. It addressed legislation introduced by Sen. Barbara Boxer (D, Calif.) that would require mandatory labeling of GM foods. "Mandatory labeling of all foods derived from biotechnology would . . . send the misleading message that the government is not confident of the safety of the U.S. food supply," the letter states. The American Crop Protection Assn. and the National Food Processors Assn., among others, point out that the FDA has extensively researched GM products and deemed them safe, requiring labeling only in certain instances. The costs associated with such labeling would be enormous as well, they note, because bioengineered ingredients would have to be segregated from "the farm to the supermarket." "It is a lot of added cost for no perceived benefit, because [genetically modified food] is safe," says Gene Grabowski, vice president, communications, Grocery Manufacturers of America. In introducing her legislation, Sen. Boxer noted that many countries outside the U.S. already require that genetically altered foods be labeled. "It is only fair that American consumers be given similar information," she says. To date the biotechnology debate has been waged much more vocally outside the U.S. than within its borders. Evidence of widespread U.S. consumer concern about genetically altered foods is sparse. Late last year the FDA held public hearings to gather consumer comment on its policies regarding bioengineered foods but has yet to issue any formal statement of findings. Only a handful of companies have publicly taken a stance on bioengineered foods. Among them is Frito-Lay Inc., Plano, Tex., which identified consumer concern as a factor in its decision to ask farmers who supply it not to grow genetically altered corn. What is the future of bioengineered foods in the U.S.? It is much too early to tell, but vigorous debate is unlikely to end any time soon. Bridge News contributed to this report.