Hazardous environmental exposures are frequent among infants and children, as well as during fetal life, and constitute an important public health issue. They are a source of substantial avoidable childhood morbidity and mortality, considerable parental stress, and significant healthcare expenses. The adverse impacts of environmental pollution on the health of children are formidable, with staggering costs to families, the healthcare system, and society. Trasande and Liu estimated the costs of environmental factors contributing to childhood conditions like prenatal exposure to methylmercury, intellectual disabilities, attention deficit hyperactivity syndrome, asthma, autism, and childhood cancers in the U.S. at $76.6 billion (2008 dollars).1 Researchers assessed the aggregated economic impact on children’s health of industrial emissions of mercury at $8.7 billion (2000 dollars) for each annual US birth cohort, with $1.3 billion attributable to mercury emitting coal-fired power plants.2 A 2019 study found both indirect and direct costs of asthma alone in the US exceed $5 billion per year.3 The annual costs associated with air pollution attributable to anthropogenic airborne particulates (PM2.5) exceed $4.8 billion and are likely a gross under-estimate.4 Children and families living in under resourced and otherwise disadvantaged communities often bear a disproportionate share of toxic environmental exposures5, 6. Parents naturally turn to their children’s clinicians for counsel and treatment when such environmental contamination risks the health of their children. And yet, many health professionals are not well-prepared to recognize exposures, manage exposed patients, and provide appropriate counseling to meet the needs of children, their families, and the communities in which they live. Previous studies have reported on the lack of training in pediatric environmental health topics either in medical school or during residency7, 8. Not surprisingly, clinicians in practice have reported that they lack the knowledge and skills needed to feel competent in counseling families regarding some common environmental concerns9, 10, 11, although such counseling is increasingly seen as important12, 13. Pediatric Environmental Health Specialty Units (PEHSUs) were created to address this gap in training and expertise. PEHSUs provide an important source of environmental medicine expertise, providing consultations and education to address complex environmental exposure scenarios.

Executive Order 13045 signed by President William Clinton in 1997 called for federal agencies to ensure the protection of children from environmental hazards14. Subsequent to that order, PEHSUs were created in 1998 by the Agency for Toxic Substances and Disease Registry (ATSDR) and have had longstanding support from ATSDR and the U.S. Environmental Protection Agency (EPA). PEHSUs are staffed by nurses and physicians with advanced training and expertise in pediatric and reproductive environmental health. They are assisted by support staff including program coordinators, managers, administrators, educators, and consultants. The history of the incremental development of the 10 regional PEHSUs across the U.S. (Figure) has been well-described15, 16, 17. In short, two toxic exposure incidents in the 1990s – one involving mercury and the other involving methyl parathion - prompted the ATSDR to launch the Child Health Initiative in 1996. This effort was designed to: 1). Promote child health practices in all of ATSDR’s programs and activities; 2). Identify opportunities for new projects that benefit infants, children, and youth; and 3). Solicit input and disseminate information through a network of external partnerships. ATSDR subsequently entered into a cooperative agreement with the Association of Occupational & Environmental Clinics (AOEC) – a private non-profit organization which would serve as the national manager of regional sites of expertise. The first two PEHSUs were established with Federal funding - Region 1 PEHSU in Boston, Massachusetts and Region 10 PEHSU in Seattle, Washington - by the end of 1998. The following year, the Region 2 PEHSU was created with non-federal funding at Mt Sinai Hospital in New York City. By 2002, PEHSUs were established in each of the 10 federal regions and federally funded, with the EPA joining the ATSDR in the initiative. Establishing units across the U.S. allowed each PEHSU to understand local environmental concerns, develop a trusted reputation in the region, and deliver timely and relevant consultative and educational services that met regional needs. PEHSUs engage with health professionals, parents, schools, community groups, and others as well as federal, state, local, and tribal government agencies. They provide community education and outreach, health professional education, and consultations to health professionals and communities impacted by environmental hazards that affect reproductive and children’s health. PEHSUs’ impacts fall into four areas broadly corresponding with program objectives to reduce environmental disease and disability by improving prevention, detection, and mitigation. These four impact areas are: 1) building professional capacity; 2) educating communities; 3) coordinating response efforts and providing technical assistance; and 4) providing individual consultation and care coordination. In this study, we review PEHSUs’ work, productivity, and impacts on the communities, health professionals, and others they serve.