Food and Drug Administration scientists are often subjected to inappropriate political and commercial interference that compromises their mission to protect public health and safety, according to the findings of a survey released yesterday by two public interest groups. 

The Union of Concerned Scientists and Public Employees for Environmental Responsibility said their survey of 997 FDA staff members suggests the "culture of science is under attack and struggling at the FDA." 

"Science must be the driving force for decisions made at the FDA. These disturbing survey results make it clear that inappropriate interference is putting people in harm's way," said Francesca Grifo, a senior scientist with the Union of Concerned Scientists. 

The FDA strongly disputed the conclusions. 

"The survey is highly unscientific, with a number of leading questions and innuendo, and it is unclear what percentage of those who replied to it are actually involved in scientific decision making here at FDA," agency spokeswoman Julie Zawisza said. 

The survey found about 17 percent of respondents said they had been asked by "FDA decision makers," for nonscientific reasons, to exclude or alter technical information or their conclusions in an FDA document. 

More than 40 percent said they knew of cases where political appointees had inappropriately injected themselves into FDA determinations or actions, and 47 percent said they knew of situations where "commercial interests" improperly tried to have an FDA conclusion reversed, withdrawn or modified. 

The report is the latest in a series of criticism of the Bush administration for distorting or censoring scientific findings or manipulating the scientific process at various government agencies. 

The FDA itself has been under repeated attack, including charges that it withheld approval of an over-the-counter emergency contraceptive to appease religious conservatives and has eased up on enforcement despite recommendations of field investigators. 

It also has been accused of suppressing and seeking retribution against FDA experts concerned about potential suicide risks associated with antidepressants and the heart attack risks of the withdrawn painkiller Vioxx. 

Zawisza, the FDA spokeswoman, acknowledged members of the agency's staff routinely have discussions, debates and even disagreements, but said final agency decisions are based on the facts and a disciplined process. 

"FDA would expect more rigor to support such far-reaching allegations and conclusions," she said of the survey. "We would expect others trained in survey methodology to question the validity of this survey and its findings, as do we." 

The survey was sent earlier this year to 5,918 FDA scientists, and 997 or 17 percent, responded. Sixty- two percent were senior scientists, and almost a third of those responding to the questionnaire had been with the FDA more than 15 years. 

Among the survey's other findings: 

 Only half (51 percent) of the scientists felt FDA was acting effectively to protect public health. 

 Two in five (40 percent) said they could not publicly express concerns about public health for fear of retaliation. 

 Nearly 70 percent said they do not believe the FDA has sufficient resources to effectively perform its mission. 

 Forty percent described morale as poor or extremely poor, and only 32 percent said the agency is moving in the right direction. 

Susan Wood, a former FDA assistant commissioner for women's health, said the survey reflects longstanding concerns within the agency. But Wood, who quit last year after charging political interference with the emergency contraceptive case, said "some things have gotten worse" under the Bush administration. 

Sen. Charles Grassley (R-Iowa), a vocal critic of the FDA, said the survey echoes views and allegations scientists report to Congress on a regular basis. 

"The leaders of the FDA would be well-served to listen to what the FDA scientists are saying in this survey," said Grassley.