2027 ICD-10-CM Diagnosis Code W99Exposure to other man-made environmental factors

ICD-10-CM Codes›V01–Y99›W85-W99›W99

ICD-10-CM W99
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

W99 is a non-billable ICD-10-CM category code for exposure to other man-made environmental factors, so it cannot be submitted on claims. Use a more specific code from this category instead, such as W99.XXXA, W99.XXXD, and W99.XXXS.

Code Identity

ICD-10-CM Code
W99
Billable Status
No — Non-Billable Category
Code Describes
Exposure to other man-made environmental factors
Short Description
Exposure to other man-made environmental factors
Same as the full description in the CMS dataset.
Chapter
W85-W99
Exposure to electric current, radiation and extreme ambient air temperature and pressure

Code Classification

ChapterV01–Y99External causes of morbidity and mortality
SectionW85-W99Exposure to electric current, radiation and extreme ambient air temperature and pressure
CategoryW99Exposure to other man-made environmental factors
This CodeW99Exposure to other man-made environmental factors

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to W99: its own notes plus those printed at block W85-W99 and Chapter 20. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block W85-W99 Exposure to electric current, radiation and extreme ambient air temperature and pressure applies to 99 codes
  • exposure to:
  • failure in dosage of radiation or temperature during surgical and medical care (Y63.2-Y63.5)
  • lightning (T75.0-)
  • natural cold (X31)
  • natural heat (X30)
  • natural radiation NOS (X39)
  • radiological procedure and radiotherapy (Y84.2)
  • sunlight (X32)

Notes

General instructions on how these codes are used.

From Chapter 20 (V00-Y99) External causes of morbidity and mortality applies to 7,461 codes
  • This chapter permits the classification of environmental events and circumstances as the cause of injury, and other adverse effects. Where a code from this section is applicable, it is intended that it shall be used secondary to a code from another chapter of the Classification indicating the nature of the condition. Most often, the condition will be classifiable to Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88). Other conditions that may be stated to be due to external causes are classified in Chapters I to XVIII. For these conditions, codes from Chapter 20 should be used to provide additional information as to the cause of the condition.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

  • The appropriate 7th character is to be added to code W99
Values for category W99 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index; each main term links to its index entry.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About W99Overview

What is the ICD-10 code for exposure to other man-made environmental factors?

W99 is the ICD-10-CM category for exposure to other man-made environmental factors, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is W99 (Exposure to other man-made environmental factors) a billable code?

No. This is a category header that groups the codes for exposure to other man-made environmental factors, and headers cannot be submitted on claims. Claims for exposure to other man-made environmental factors need a more specific code from this category, such as W99.XXXA, W99.XXXD, and W99.XXXS.

Can W99 be reported with a code from T75.0?

Not as a rule. The Excludes1 note at block W85-W99, which applies to W99, lists "lightning (T75.0-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).