A major environmental group yesterday urged the Carter administration to drop its reported plan to allow the continued use of health-damaging lead in gasoline.

The Natural Resources Defense Council, in a letter to presidential assistant Stuart E. Eizenstat, charged that the plan would subvert an important public-health advance.

NRDC and other environmental and health groups successfully sued the Environmental Protection Agency and won an EPA agreement to require lead reductions in gasoline by this October.

Various studies have shown that lead in gasoline is associated with significant alterations of child behavior, particularly in inner city neighborhoods, where auto exhaust plooution is more severe.

The lead content inthe air pollution, NRDC attorney Daivd Schoenbrod said in his letter to Eizenstat, is known to cause "attentional disorders, learning disabilities or emotional disturbances."

NRDC said it was "alarmed" bvy reports that Energy Secretary James R. Schlesinger is recommending suspension of the October lead deadline as part of the administration's response to petroleum supply shortages caused by the Iranian revolution.

Schlesinger and Department of Energy officials have said that leaving lead in gasoline will produce an extra 500,000 barrels pewr day from Xisting crude petroleum stocks.

"Suspending the October public-health deadline has no bearing on this summer's gasoline supply," Schoenbrod said, "and the DOE has not and cannot document the need for an emergency decision."

He said that Schlesinger, in recommending the suspension, "has grasped for a highly visible straw that will not help the country get through a crude oil shortage, but will hurt the health of children"

NRDC asked Elizenstat to intervene -- by reversing Schlesinger -- before President Carter next week announces the steps his administration plans to take to deal with the petroleum supply shortfall.

An aide to Eizenstat said his office would have no comment on the NRDC charge, was not aware if the letter had arrived and, if it had, would be considered along with "thousands of other letters we receive on energy."