2026 ICD-10-CM Diagnosis Code T59.93XSToxic effect of unspecified gases, fumes and vapors, assault, sequela
T59.93XS is a billable ICD-10-CM diagnosis code for toxic effect of unspecified gases, fumes and vapors, assault, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. Coders also document this condition as assault by poisoning. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T59.93XS is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Assault by poisoning
- Assault by poisoning by gas or vapor
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.
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 |
|---|---|---|---|---|---|---|
| Fumes (from) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::carbon monoxide | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::charcoal (domestic use) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::chloroform | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::coke (in domestic stoves, fireplaces) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::corrosive NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::ether | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::freons | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::hydrocarbons | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::hydrocarbons::petroleum (liquefied) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::hydrocarbons::petroleum (liquefied)::distributed through pipes (pure or mixed with air) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::lead | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::metal | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::nitrogen dioxide | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::pesticides | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::petroleum (liquefied) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::petroleum (liquefied)::distributed through pipes (pure or mixed with air) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::polyester | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::specified source NEC [See Also: substance specified] | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Fumes (from)::sulfur dioxide | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::acetylene | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::acetylene::incomplete combustion of | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::air contaminants, source or type not specified | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::anesthetic | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::blast furnace | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::butane | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::carbon monoxide | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::chlorine | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::coal | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::cyanide | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::dicyanogen | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::domestic | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::exhaust | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::from utility (for cooking, heating, or lighting) (after combustion) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::from utility (for cooking, heating, or lighting) (after combustion)::prior to combustion | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::from wood- or coal-burning stove or fireplace | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel] | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel]::industrial use | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel]::prior to combustion | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel]::utility | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel]::utility::in mobile container | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel]::utility::incomplete combustion of | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::fuel (domestic use) (after combustion) [See Also: Carbon, monoxide, fuel]::utility::piped (natural) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::garage | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::hydrocarbon NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::hydrocarbon NEC::incomplete combustion of | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::hydrocarbon NEC::liquefied | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::hydrocarbon NEC::liquefied::piped | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::hydrocyanic acid | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::illuminating (after combustion) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::illuminating (after combustion)::prior to combustion | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::incomplete combustion, any | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::kiln | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::lacrimogenic | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::liquefied petroleum | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::marsh | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::motor exhaust, not in transit | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::mustard, not in war | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::natural | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::nerve, not in war | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::oil | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::petroleum (liquefied) (distributed in mobile containers) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::petroleum (liquefied) (distributed in mobile containers)::piped (pure or mixed with air) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::piped (manufactured) (natural) NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::producer | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::propane | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::refrigerant (chlorofluoro-carbon) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::refrigerant (chlorofluoro-carbon)::not chlorofluoro-carbon | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::sewer | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::specified source NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::stove (after combustion) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::stove (after combustion)::prior to combustion | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::tear | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::therapeutic | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::utility (for cooking, heating, or lighting) (piped) NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::utility (for cooking, heating, or lighting) (piped) NEC::in mobile container | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::utility (for cooking, heating, or lighting) (piped) NEC::incomplete combustion of | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::utility (for cooking, heating, or lighting) (piped) NEC::piped (natural) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::water | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Gas NEC::water::incomplete combustion of | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Lung irritant (gas) NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Nerve gas, not in war | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Sewer gas | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Vapor [See Also: Gas] | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Vapor [See Also: Gas]::kiln (carbon monoxide) | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Vapor [See Also: Gas]::lead | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
| Vapor [See Also: Gas]::specified source NEC | T59.91 | T59.92 | T59.93 | T59.94 | – | – |
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 T59.93XS to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T59.93XSOverview
Is T59.93XS (Toxic effect of unspecified gases, fumes and vapors, assault) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of unspecified gases, fumes and vapors, assault, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T59.93XS mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the toxic effect of unspecified gases, fumes and vapors, assault itself has resolved, not the original event.
What MS-DRG does T59.93XS group to?
When toxic effect of unspecified gases, fumes and vapors, assault, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T59.93XS exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for toxic effect of unspecified gases, fumes and vapors, assault, sequela on inpatient claims.
What is the ICD-9 equivalent of T59.93XS?
Under the General Equivalence Mappings, toxic effect of unspecified gases, fumes and vapors, assault, sequela converts to ICD-9-CM 909.1 (late eff nonmed substanc). 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.
