T59 vs Z77
T59 (Toxic effect of other gases, fumes and vapors) compared with Z77 (Other contact with and (suspected) exposures hazardous to health), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. T59 carries an Excludes1 note covering Z77: “contact with and (suspected) exposure to toxic substances (Z77.-)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| T59Toxic effect of other gases, fumes and vapors | Z77Other contact with and (suspected) exposures hazardous to health | |
|---|---|---|
| Billing status | Non-billable header Report instead: T59.0X1A, T59.0X1D, T59.0X1S, T59.0X2A, T59.0X2D | Non-billable header |
| Classification | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) | Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99) |
| Definition | Toxic effect of other gases, fumes and vapors is a non-billable ICD-10-CM category code (T59). | Other contact with and (suspected) exposures hazardous to health is a non-billable ICD-10-CM category code (Z77). |
| 7th character | The appropriate 7th character is to be added to each code from category T59 | — |
| Includes | aerosol propellants | contact with and (suspected) exposures to potential hazards to health |
| Use additional code | code(s): for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) personal history of foreign body fully removed (Z87.821) | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources