Washington ? The government is using outdated science in assessing the health risks of more than 3 million tons of sewage sludge used as fertilizer each year, a panel of scientists said Tuesday.

When the Environmental Protection Agency set standards in 1993 on the use of “biosolids” for treating soil, it used an unreliable 1988 survey to identify hazardous chemicals in sewage sludge from wastewater treatment plants, said the National Research Council panel.

Since then, the panel said, technology for detecting pathogens and the methods for assessing health risks posed by exposure to chemicals in sludge have developed significantly.

“There is a serious lack of health-related information about populations exposed to treated sewage sludge,” said the panel’s chairman, Thomas A. Burke, a health policy and management professor at Johns Hopkins University’s Bloomberg School of Public Health in Baltimore.

The panel’s report found no documented scientific evidence of the EPA’s standards failing to protect public health. But it said the agency needs to do more scientific work so it can “reduce persistent uncertainty” about the risks to people from exposure to chemicals and disease-causing pathogens in sludge used as fertilizer.

The EPA hasn’t done a substantial reassessment to determine whether its standards are supported by current scientific data and risk assessment methods, the panel said.