Skip to content
Dx

ICD-10-CM 2027 diagnosis code

T59.4Toxic effect of chlorine gas

Not billable — use a more specific codeRequires 7th character

T59.4 is a header code, so it can't be reported by itself. Choose one of the 1 more specific codes beneath it and add the required 7th character.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T59.4

T59.4 is the ICD-10-CM diagnosis code for toxic effect of chlorine gas. It belongs to category T59 (toxic effect of other gases, fumes and vapors), block T51-T65 (toxic effects of substances chiefly nonmedicinal as to source) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 1 subcodes must be used instead.

Within T59 (toxic effect of other gases, fumes and vapors), T59.4 is specifically for toxic effect of chlorine gas. Related codes cover nitrogen oxides (T59.0), sulfur dioxide (T59.1), formaldehyde (T59.2), lacrimogenic gas (T59.3), fluorine gas and hydrogen fluoride (T59.5), hydrogen sulfide (T59.6), carbon dioxide (T59.7), other specified gases, fumes and vapors (T59.8) and 1 more.

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

7th character

The appropriate 7th character is to be added to each code from category T59

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Notes that apply from higher levels

Instructions written at a parent level also apply to T59.4.

› From T59 Toxic effect of other gases, fumes and vapors
Includes
  • aerosol propellants
Excludes1
  • chlorofluorocarbons (T53.5)

Broader instructions also apply from T51-T65 Toxic effects of substances chiefly nonmedicinal as to source and Chapter 19: Injury, poisoning and certain other consequences of external causes.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about T59.4

Is T59.4 billable?

No. T59.4 is a header code. Report one of its more specific subcodes instead.