SACCHARIN, TRIS, AEROSOLS, hair dyers - what else will we all be told may be linked to cancer? And at what point will the government let us know - before the product hits the market? Or not until everybody's buying it while some agency still hasn't finished testing it? More and more people today would like answers, particularly in light of the record of uncertainty and often conflicting opinions of various federal agencies dealing with toxic substances or carcinogens (cancer-causing chemicals). So far, the federal government has made only slight progress toward any unified, reliable system for identifying and regulating potential cancer-causing substances. Moreover, there's been all too little interest at the White House in giving this effort the support it deserves.

One leading advocate of a better national system to protect people from hazardous substances before these items reach the market is Barbara Hackman Franklin, vice chairman of the Consumer Product Safety Commission. She has been urging the administration to initiate a series of regional hearings involving scientists, government officials and consumer and other concerned citizens group, to consider ways to improve public protection without imposing unnecessary or unreasonable burdens on business. The eventual objective would be the development of a national policy for research and regulation.

As it stands, the government has surprisingly few carcinogen-screening tests that are reliable, fast and inexpensive; more often than not, test results are inconsistent - making it difficult for regulators to know which chemicals really may be hazardous. Not only is there considerable official uncertainty, but those regulations that do exist haven't been well understood by the public. For the most part, Ms. Franklin notes, "what we have . . . is government representatives talking to other government representatives."

At least these various government agencies have begun to share facilities, laboratories and information, and are working on testing standards and guidelines in efforts to define what constitutes a "risk." Also, the staff of the Product Safety Commission has recommended that this agency adopt a "safe rather than sorry" policy in banning potential carcinogenic hazards. Certainly much of the publi's confusion could be eliminated if the government would concentrate its energies and policies on forewarning people. But without White House leadership to develop some uniform, understandable national policy, the tests and warnings and bans may simply continue to confuse consumers - without necessarily protecting them.