2026 ICD-10-CM Diagnosis Code T59.891AToxic effect of other specified gases, fumes and vapors, accidental (unintentional), initial encounter
T59.891A is a billable ICD-10-CM diagnosis code for toxic effect of other specified gases, fumes and vapors, accidental (unintentional), initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 917 through 918, 928 through 929. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: intent of injury, accidental/unintentional; External cause codes: poisoning by non-drug; and Toxic effects, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Accidental poisoning by acetylene
- Accidental poisoning by bromine compounds
- Accidental poisoning by butane
- Accidental poisoning by gas distributed by pipeline
- Accidental poisoning by liquefied petroleum gas distributed in mobile containers
- Accidental poisoning by liquefied petroleum gas distributed through pipes
- Accidental poisoning by methyl bromide
- Accidental poisoning by petroleum products
- Accidental poisoning by piped natural gas
- Accidental poisoning by propane
- Accidental poisoning caused by halogenated hydrocarbon
- Acroosteolysis
- Alkane poisoning
- Ammonia encephalopathy
- Automotive products causing toxic effect
- Brake fluid causing toxic effect
- Bromine compound poisoning
- Injury due to legal intervention by gas
- Injury due to legal intervention by tear gas
- Injury due to poison gas weapon
- Methane poisoning
- Mustard gas poisoning
- Occupational acroosteolysis
- Poisoning caused by halogenated hydrocarbon
- Poisoning due to irritant gas
- Poisoning due to nerve gas
- Poisoning due to vesicant gas
- Polymer fume fever
- Teflon poisoning
- Toxic effect of butane
- Toxic effect of hydrocarbon gas
- Toxic effect of liquefied petroleum gas
- Toxic effect of nitrous fumes
- Toxic effect of phosgene
- Toxic effect of polyester fumes
- Toxic effect of propane
- Toxic inhalation-induced febrile illness
- Vinyl chloride disease
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Toxic effect of other gases, fumes and vapors (T59). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Acroosteolysis
a condition that is characterized by degeneration of the distal phalanges.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
| Substance | Accidental | Self-harm | Assault | Undetermined | Adverse Effect | Underdosing |
|---|---|---|---|---|---|---|
| Acetylene (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acetylene (gas)::dichloride | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acetylene (gas)::incomplete combustion of | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acetylene (gas)::industrial | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acetylene (gas)::tetrachloride | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acetylene (gas)::tetrachloride::vapor | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acrolein (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Acrolein (gas)::liquid | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ammonia (fumes) (gas) (vapor) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ammonia (fumes) (gas) (vapor)::aromatic spirit | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ammonia (fumes) (gas) (vapor)::liquid (household) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Brake fluid vapor | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Butane (distributed in mobile container) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Butane (distributed in mobile container)::distributed through pipes | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Butane (distributed in mobile container)::incomplete combustion | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Combustion gas (after combustion) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Combustion gas (after combustion)::prior to combustion | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Cyanic acid (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Cyanogen (chloride) (gas) NEC | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Diazomethane (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Diborane (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Dichloroethyl sulfide, not in war | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Dichloroformoxine, not in war | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Domestic gas (after combustion) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Domestic gas (after combustion)::prior to combustion | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethidium chloride (vapor) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::anesthetic (general) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::chlorohydrin | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::chlorohydrin::vapor | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::dichloride | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::dichloride::vapor | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::dinitrate | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::glycol (s) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::glycol (s)::dinitrate | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::glycol (s)::monobutyl ether | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::imine | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::oxide (fumigant) (nonmedicinal) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ethylene (gas)::oxide (fumigant) (nonmedicinal)::medicinal | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ferrovanadium (fumes) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Firedamp | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Helium (nonmedicinal) NEC | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Helium (nonmedicinal) NEC::medicinal | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrocarbon gas | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrocarbon gas::incomplete combustion of | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrocarbon gas::liquefied (mobile container) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrocarbon gas::liquefied (mobile container)::piped (natural) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::arsenide | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::arseniureted | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::chloride | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::cyanide (salts) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::cyanide (salts)::gas | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::Fluoride | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::Fluoride::vapor | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::peroxide | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::phosphureted | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::sulfide | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::sulfide::arseniureted | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Hydrogen::sulfureted | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Liquefied petroleum gases | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Liquefied petroleum gases::piped (pure or mixed with air) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Marsh gas | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Methane | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Methanethiol | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Ozone | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Phosgene (gas) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Polyester fumes | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Polytetrafluoroethylene (inhaled) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Propane (distributed in mobile container) | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Propane (distributed in mobile container)::distributed through pipes | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Propane (distributed in mobile container)::incomplete combustion | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Propylene | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
| Sternutator gas | T59.891 | T59.892 | T59.893 | T59.894 | – | – |
Patient EducationClinical
Poisoning
A poison is any substance that is harmful to your body. You might swallow it, inhale it, inject it, or absorb it through your skin. Any substance can be poisonous if too much is taken. Poisons can include:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T59.891A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T59.891AOverview
Is T59.891A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of other specified gases, fumes and vapors, accidental (unintentional), initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T59.891A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for toxic effect of other specified gases, fumes and vapors, accidental (unintentional), such as an emergency visit or first evaluation.
What MS-DRG does T59.891A group to?
When toxic effect of other specified gases, fumes and vapors, accidental (unintentional), initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 917, 918, 928, 929, with relative weights from 0.8571 to 7.1727 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of T59.891A?
Under the General Equivalence Mappings, toxic effect of other specified gases, fumes and vapors, accidental (unintentional), initial encounter converts to ICD-9-CM 987.9 (toxic eff gas/vapor NOS) and E869.8 (acc poison-gas/vapor NEC). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
