Exposure to other man-made environmental factors (W99) ICD-10-CM
The W99 code range covers exposure to other man-made environmental factors with 4 ICD-10-CM diagnosis codes. 3 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
7th Character Note
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
- The appropriate 7th character is to be added to code W99
7th Character
Indicates that a seventh character is to be assigned to codes in a subcategory.
- A - initial encounter
- D - subsequent encounter
- S - sequela
Codes in the W99 Range 4 codes · 3 billable
About the W99 Code Range
The ICD-10 code W99 is used to identify injuries caused by exposure to various man-made environmental factors, such as sudden changes in air pressure experienced in aircraft or during diving. These codes distinguish between initial treatment, follow-up care, and complications arising after the injury.
This section specifically covers incidents like rapid decompression accidents, which may also be referred to as accidents due to sudden loss of aircraft cabin pressure or pressure changes in diving. For medical coders and healthcare professionals, the codes W99.XXXA, W99.XXXD, and W99.XXXS indicate initial encounter, subsequent encounter, and sequela, respectively, for these types of environmental exposures. Understanding these distinctions helps accurately document and track the patient’s clinical course after such unique man-made environmental injuries. Using the correct ICD-10 code for exposure to other man-made environmental factors ensures precise classification of pressure-related accidents, aiding in proper treatment planning and data collection.
Questions About This Page
How many billable codes are in the W99 range?
Of the 4 codes in this range, 3 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the W99 range classify?
The range classifies exposure to other man-made environmental factors. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
