WASHINGTON — Herbert L. Needleman, a pediatrician and psychiatrist who demonstrated in the late 1970s that children exposed to even small amounts of lead could suffer intellectual and behavioral deficits, a finding that spurred and emboldened wide-ranging safety regulations, died July 18 at an assisted-living center in Pittsburgh. He was 89.

The cause was pulmonary edema, said his daughter, Sara Needleman Kline.

Dr. Needleman, who was associated most recently with the University of Pittsburgh, spent the better part of his professional life crusading against what he termed the ‘‘national disaster’’ of lead poisoning among children.

His research attracted the anger of lead industry executives and the criticism of some scientific researchers who considered his research flawed. But Dr. Needleman also earned the admiration of colleagues who regarded him as a dogged and creative scientist, one who forced national attention on a scourge that threatened the well-being and future of millions of children.

Before environmental laws curtailed its application, lead was widely added to paint used in homes and schools, to varnish used on toys, to plumbing pipes, and to fuel for cars.

By the time Dr. Needleman was practicing medicine in the 1950s, physicians knew significant exposure to lead could cause lead poisoning, a condition that, in extreme cases, could result in seizures and death. The effects of minor exposure, however, were not well understood.

Dr. Needleman first encountered the toxin in the infant ward at a children’s hospital in Philadelphia. If the child ‘‘eats more paint,’’ he recalled telling her mother, ‘‘there’s no question she’ll be brain damaged.’’

‘‘Where can I go?’’ the mother replied. ‘‘Any house I can afford will be no different from the house I live in now.’’

Haunted by the experience, Dr. Needleman devised an experiment years later, while working at Harvard Medical School, to measure the effects of lead poisoning. He and colleagues collected and analyzed baby teeth of Boston-area children. The pulp in teeth, more than blood samples, reveals the long-term buildup of lead in the body.

The researchers measured the participants’ IQs, as well as surveying teachers about their classroom behavior.

The results, published in the New England Journal of Medicine in 1979, were marked. The mean IQ of children with high lead levels was more than 4 points lower than that of children with low lead levels.

Teachers also reported that children with high lead levels more commonly had difficulty following instructions. Those children also were more likely to be described as hyperactive or impulsive. A follow-up survey of the same students in 1990 showed a link between lead poisoning and difficulty reading and completing high school.

The study was significant because it suggested even small amounts of lead were enough to produce pernicious effects. It helped highlight the socioeconomic element of lead poisoning, which posed a particular threat to families living near certain industrial facilities or in poor communities with substandard construction.

Dr. Needleman’s research was credited with accelerating the elimination of lead from gasoline, with the establishment of a ban on lead pipes, and with stricter enforcement of lead paint abatement and disclosure regulations. According to the Centers for Disease Control and Prevention, ‘‘no safe blood lead level in children has been identified.’’

In the early 1990s, after years of opposition by the lead industry and scientists who supported its position, Dr. Needleman’s research was investigated by the federal Office of Research Integrity. The probe cleared him of accusations of scientific misconduct but cited errors such as a failure to obtain a representative population for his experiment. The probe did not find that any such mistakes influenced his ultimate conclusions.

He subsequently received awards including a $250,000 Heinz Award, in memory of the late US senator John Heinz, a Pennsylvania Republican.

‘‘It is not surprising that Dr. Needleman’s work made him a frequent target of criticism by the lead industry, or that he was once forced to defend himself against charges of scientific fraud and misconduct,’’ the citation said. ‘‘Not only was he exonerated, but he fought for and won the right for those accused of such charges to an open hearing with legal representation — a right that has benefited the entire scientific community.’’

Herbert Leroy Needleman was born in Philadelphia on Dec. 13, 1927. His mother was a Jewish immigrant from Russia whose family sold pickles, building a pushcart operation into a company that later merged with Vlasic. His father was a furniture salesman.

Dr. Needleman received a bachelor’s degree from Muhlenberg College and a medical degree from the University of Pennsylvania. He served in the Army and the Army Reserve, attaining the rank of captain.

During the Vietnam War, he was arrested and spent a night in jail with Benjamin Spock, the renowned pediatrician, for their participation in an antiwar protest. While teaching at Temple University in the 1960s, he chaired the Committee of Responsibility to Save War-Burned and War-Injured Vietnamese Children, a civilian group that sought to bring wounded children to the United States for medical care.