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Key Concepts
  • Nitrate toxicity is a preventable cause of methemoglobinemia.
  • Infants younger than 4 months of age are at particular risk of nitrate toxicity from contaminated well water.
  • The widespread use of nitrate fertilizers increases the risk of well-water contamination in rural areas.
About This and Other Case Studies in Environmental Medicine

This educational case study document is one in a series of self-instructional modules designed to increase the primary care provider’s knowledge of hazardous substances in the environment and to promote the adoption of medical practices that aid in the evaluation and care of potentially exposed patients. The complete series of Case Studies in Environmental Medicine is located on the ATSDR Web site at URL: In addition, the downloadable PDF [PDF – 1.1 MB] version of this educational series and other environmental medicine materials provides content in an electronic, printable format.


We gratefully acknowledge the work of the medical writers, editors, and reviewers in producing this educational resource. Contributors to this version of the Case Study in Environmental Medicine are listed below.

Please Note: Each content expert for this case study has indicated that there is no conflict of interest that would bias the case study content.

CDC/ATSDR Author(s): Kim Gehle MD, MPH

CDC/ATSDR Planners: Charlton Coles, Ph.D.; Kimberly Gehle MD; Sharon L. Hall Ph.D.; Delene Roberts MSMHC; Julia Smith MPH, CHES

CDC/ATSDR Independent Reviewers: Hana R. Pohl MD, PhD; Michelle Watters MD, PhD, MPH

CDC/ATSDR Commenter’s: Art Chang MD, MS; Lorraine Backer PhD, MPH

Disclaimer and Disclosure


The state of knowledge regarding the treatment of patients potentially exposed to hazardous substances in the environment is constantly evolving and is often uncertain. In developing its educational products ATSDR has made a diligent effort to ensure the accuracy and the currency of the presented information. ATSDR, however, makes no claim that the environmental medicine and health education resources discussed in these products comprehensively address all possible situations related to various substances. The products are intended for educational use to build the knowledge of physicians and other health professionals in assessing the conditions and managing the treatment of patients potentially exposed to hazardous substances. The products are not a substitute for a health-care provider’s professional judgment. Please interpret the environmental medicine and the health education resources in light of specific information regarding the patient and in conjunction with other medical authorities.

Use of trade names in ATSDR products is for identification purposes only and does not imply endorsement by the Agency for Toxic Substances and Disease Registry or the U.S. Department of Health and Human Services.

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U.S. Department of Health and Human Services
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
Environmental Medicine Branch