MCMCB Pro
W40.1

W40.1Explosion of explosive gases

Non-billable headerICD-10-CM

W40.1 is a non-billable header ICD-10-CM code for explosion of explosive gases. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

The appropriate 7th character is to be added to each code from category W40

A
initial encounter
D
subsequent encounter
S
sequela

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Explosion of acetylene
  • Explosion of butane
  • Explosion of coal gas
  • Explosion in mine NOS
  • Explosion of explosive gas
  • Explosion of fire damp
  • Explosion of gasoline fumes
  • Explosion of methane
  • Explosion of propane

Risk adjustment

W40.1 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

How W40.1 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to W40.1.

  • Explosionacetylene
  • Explosionanesthetic gas in operating room
  • Explosionbutane
  • Explosioncoal gas
  • Explosionfire-damp
  • Explosiongas(coal) (explosive)
  • Explosiongasoline not in moving motor vehicle(fumes) (tank)
  • Explosionmethane
  • Explosionmine
  • Explosionpropane
  • Ignitionanesthetic gas in operating room
  • Explosionexplosivegas

Code to one of these instead W40.1

3 child codes. Green means billable.

Related codes at this level

Codes that share W40. If W40.1 is not quite right, the correct code is usually one of these.

Questions about W40.1

Is W40.1 a billable ICD-10-CM code?
No. W40.1 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does W40.1 sit in the tabular list?
External causes of morbidity (V00-Y99), in the block Exposure to inanimate mechanical forces (W20-W49).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.