The Short Version
Robust peer-reviewed evidence and major health authorities (EPA, WHO, CDC, NIEHS) confirm that childhood exposure to specific environmental toxins — particularly lead, air pollution, and certain pesticides — is causally linked to long-term chronic health outcomes including neurodevelopmental disorders and respiratory disease. The claim is well-supported for these established cases. However, the blanket framing overstates certainty for some toxin-outcome pairs where evidence remains associational or contested, such as certain cancers and endocrine-related conditions.