This page compares two distinct NUCC-taxonomy specialties tracked by the CMS National Plan and Provider Enumeration System: Occupational Medicine Physician, which currently counts 2,230 enrolled providers across 52 U.S. states and territories, and Undersea and Hyperbaric Medicine (Preventive Medicine) Physician, with 243 providers across 42 states. Each clinician on these rosters selected a primary NUCC code at NPI enrollment, so the totals measure how many providers self-identify their primary practice as Occupational Medicine Physician or Undersea and Hyperbaric Medicine (Preventive Medicine) Physician rather than the total population ever trained or credentialed in either field, dual-certified clinicians show up under whichever code they registered first. Every figure is drawn from the federal National Provider Identifier Registry (CMS NPPES) - more than 7 million providers, maintained since May 2007, with 2023 Medicare Part D data, and, according to CMS, can be searched, compared, and traced in our methodology.

On national volume, Occupational Medicine Physician carries the larger provider roster (2,230 vs 243), and Occupational Medicine Physician has the wider geographic footprint at 52 states versus 42. The top Occupational Medicine Physician concentration sits in California (356 providers), while Undersea and Hyperbaric Medicine (Preventive Medicine) Physician peaks in Florida (40). The per-capita columns in the table below normalize each state's raw count against 2023 Census population estimates, which matters because absolute provider counts track population scale first and specialty density second, a small state with a strong training pipeline can out-rank a larger state on per-100K availability.

Use this comparison to understand relative availability, not to judge clinical substitutability - Occupational Medicine Physician and Undersea and Hyperbaric Medicine (Preventive Medicine) Physician are distinct specialties with different scopes of practice, training requirements, and conditions they treat, even when their NUCC categories overlap. Important: PlainDoctor is a directory of publicly available CMS government data, not medical advice, a provider rating, or a recommendation about which specialty a patient should consult. Always work with a licensed clinician to determine which specialty is appropriate for your condition, verify any specific provider through the NPPES NPI Registry and the relevant state medical board, and consult the NUCC taxonomy documentation for the formal scope-of-practice definitions behind each specialty code.