The Public Health Service and health officials objected to the USDA approval of Shell's No-Pest Strip. USDA continued to allow sales of the product for home use, and objections from other agencies were finally resolved by agreement on a series of warnings to appear on the label. A congressional investigation revealed, needless delays on the part of USDA in instituting these requirements. Warnings that the strip may not be used where food is prepared or served still do no appear on its label. In the course of this investigation, Environment was threatened by Shell Chemical Company with legal action, and Shell has consistently refused to release the research reports on which it bases its claims for the safety of the strip.