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W40

W40Explosion of other materials

Non-billable headerICD-10-CM

W40 is a non-billable header ICD-10-CM code for explosion of other materials. 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

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

  • assault by explosive material (X96)
  • explosion involving legal intervention (Y35.1-)
  • explosion involving military or war operations (Y36.0-, Y36.2-)
  • intentional self-harm by explosive material (X75)

Other codes that can never be billed with W40

These codes carry an Excludes1 note pointing at W40. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading W40 alone.

  • W20Struck by thrown, projected or falling object
  • W30Contact with agricultural machinery
  • W30.3Contact with grain storage elevator
  • W30.3XXAContact with grain storage elevator, initial encounter
  • W30.3XXDContact with grain storage elevator, subsequent encounter
  • W30.3XXSContact with grain storage elevator, sequela

Risk adjustment

W40 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.

Code to one of these instead W40

4 child codes. Green means billable.

Questions about W40

Is W40 a billable ICD-10-CM code?
No. W40 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does W40 sit in the tabular list?
External causes of morbidity (V00-Y99), in the block Exposure to inanimate mechanical forces (W20-W49).
What cannot be coded together with W40?
W40 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.
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.