At the Food and Drug Administration, employees are not allowed to hold financial interests in firms that manufacture the products the FDA regulates. At the National Institutes of Health, which conduct and support biomedical research on disease, the financial statements of workers are reviewed to make sure no one stands to gain privately from a decision NIH makes to benefit the public.

But at the Office of Technology Assessment no such rules apply.

One OTA staffer currently working on a study for Congress of unorthodox cancer treatments owns about $125,000 worth of stock in a company that makes traditional cancer drugs and chemotherapy products.

That has raised eyebrows at the National Health Federation, a nontraditional, nonprofit California group that lobbies for freedom of choice in health-care matters. The lobbyists have launched a letter-writing campaign that has OTA thinking about tightening its procedures.

OTA was created in 1972 after congressional fumbling of environmental problems in the late 1960s. Its job is to give Congress the technical expertise necessary to make decisions about medicine and science. A small office, staffed by respected scientists and overseen by a bipartisan congressional board, OTA has been heralded as a bastion of objectivity. According to Director John H. Gibbons, there are plenty of checks and balances to prevent anyone from having too much influence. Project teams, with the help of outside advisers, conduct studies for Congress. Drafts are reviewed by several sources before the final report is sent to lawmakers for approval.

''The words we write have to stand up to scrutiny,'' Gibbons told our reporter Tanya Isch. ''We're pretty doggone confident that what we take to Congress is accurate and fair.''

Maybe so, but not everyone shares Gibbons' confidence.

The case that has been drawing the most attention is the study of alternative cancer treatments such as special diets and mind healing. Dr. Roger Herdman, the man in charge of OTA's Health and Life Sciences Division, which is conducting the study, owns 50,000 shares of stock in a cancer research company, Oncogene Science Inc., worth about $125,000. The company is currently seeking FDA approval for traditional chemotherapy products and cancer drugs. Herdman also owns 10,000 shares of Angio-Medical Corp., a company that does cardiovascular disease research. His shares are worth about $65,000. And he is on the board of directors of the Medical Research Investment Fund, a mutual fund that specializes in medical research.

Clinton Ray Miller, a lobbyist for NHF, questions whether Herdman's holdings, and his past employment with Memorial Sloan-Kettering Cancer Center in New York, will affect his view of alternative cancer treatments.

Herdman told us he is willing to sell his stock if he is asked to, but he doesn't think that is necessary.

The cancer study was prompted by congressional curiosity over unorthodox cancer treatment clinics in Mexico, and the issue raises raw feelings among mainstream doctors and New Age practitioners. As such, it is likely to be a sensitive matter for Congress, which might draw up some general guidelines for evaluating unorthodox cancer treatments. But Herdman said the congressional study is just one of 20 projects his division is working on. As such, his day-to-day involvement is minimal, he said.

Herdman is not the only OTA official with investments that could be affected by OTA recommendations. Gibbons, the director, owns stock in Genentech Clinical Partners, which tests and manufactures an antitumor protein.

OTA officials must file annual financial-disclosure forms with the Senate secretary's office. But unlike the FDA and NIH, OTA does not do an internal review to check for ways an employee could make a killing in an investment. As a legislative office, the OTA isn't governed by the executive order that keeps the FDA and NIH in line.

Gibbons said he has never felt it necessary to check his staffers' portfolios because he trusts them. In fact, he believes it can be beneficial for them to dabble in industry to learn ''how ideas move through the marketplace.''

Nonetheless, Gibbons told us he is considering starting an internal review process at OTA and has asked his assistant directors to begin evaluating projects for possible conflicts. At Herdman's request, Gibbons will review Herdman's contribution to the cancer study.