2026 ICD-10-CM Diagnosis Code T30.4Corrosion of unspecified body region, unspecified degree

ICD-10-CM Codes›S00–T88›T30-T32›T30

ICD-10-CM T30.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T30.4 is a billable ICD-10-CM diagnosis code for corrosion of unspecified body region, unspecified degree. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Burn and corrosion, initial encounter.

Code Identity

ICD-10-CM Code
T30.4
Billable Status
Yes — Valid for Submission
Code Describes
Corrosion of unspecified body region, unspecified degree
Short Description
Corrosion of unspecified body region, unspecified degree
Same as the full description in the CMS dataset.
Parent Code
T30
Burn and corrosion, body region unspecified

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT30-T32Burns and corrosions of multiple and unspecified body regions
CategoryT30Burn and corrosion, body region unspecified
This CodeT30.4Corrosion of unspecified body region, unspecified degree

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acid burn of skin
  • Acute skin injury caused by corrosive substance
  • Alkali burn of skin
  • Cement burn of skin
  • Chemical burn
  • Chemical burn of skin
  • Chemical burn of skin caused by corrosive substance
  • Chemical injury of peripheral nerve
  • Dithranol burn
  • Injury due to chemical exposure
  • Injury of unknown intent by local effect of caustic substance
  • Injury undetermined whether accidentally or purposely inflicted, by caustic substances, excluding poisoning
  • Phosphorus burn of skin
  • Self-inflicted caustic burn

Coding GuidelinesGuidance

The ICD-10-CM makes a distinction between burns and corrosions. The burn codes are for thermal burns, except sunburns, that come from a heat source, such as a fire or hot appliance. The burn codes are also for burns resulting from electricity and radiation. Corrosions are burns due to chemicals. The guidelines are the same for burns and corrosions.

Sequence first the code that reflects the highest degree of burn when more than one burn is present.

  • When the reason for the admission or encounter is for treatment of external multiple burns, sequence first the code that reflects the burn of the highest degree.
  • When a patient has both internal and external burns, the circumstances of admission govern the selection of the principal diagnosis or first-listed diagnosis.
  • When a patient is admitted for burn injuries and other related conditions such as smoke inhalation and/or respiratory failure, the circumstances of admission govern the selection of the principal or first-listed diagnosis.

When coding burns, assign separate codes for each burn site. Category T30, Burn and corrosion, body region unspecified is extremely vague and should rarely be used.

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • This code is not for inpatient use. Code to specified site and degree of corrosion
  • Corrosion NOS
  • Multiple corrosion NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Corrosion(injury) (acid) (caustic) (chemical) (lime) (external) (internal)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ019
Burn and corrosion, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Burns

A burn is damage to your body's tissues caused by heat, chemicals, electricity, sunlight, or radiation. Scalds from hot liquids and steam, building fires and flammable liquids and gases are the most common causes of burns. Another kind is an inhalation injury, caused by breathing smoke.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert T30.4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
949.0 Burn NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T30.4Overview

Is T30.4 (Burn and corrosion, body region unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report corrosion of unspecified body region, unspecified degree on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of T30.4?

Under the General Equivalence Mappings, corrosion of unspecified body region, unspecified degree converts to ICD-9-CM 949.0 (burn NOS). 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.