| X39 | Exposure to other forces of nature | NON-BILLABLE CODE |
| X39.0 | Exposure to natural radiation | NON-BILLABLE CODE |
| X39.01 | Exposure to radon | NON-BILLABLE CODE |
| X39.01XA | Exposure to radon, initial encounter | BILLABLE CODE |
| X39.01XD | Exposure to radon, subsequent encounter | BILLABLE CODE |
| X39.01XS | Exposure to radon, sequela | BILLABLE CODE |
| X39.08 | Exposure to other natural radiation | NON-BILLABLE CODE |
| X39.08XA | Exposure to other natural radiation, initial encounter | BILLABLE CODE |
| X39.08XD | Exposure to other natural radiation, subsequent encounter | BILLABLE CODE |
| X39.08XS | Exposure to other natural radiation, sequela | BILLABLE CODE |
| X39.8 | Other exposure to forces of nature | NON-BILLABLE CODE |
| X39.8XXD | Other exposure to forces of nature, subsequent encounter | BILLABLE CODE |
| X39.8XXS | Other exposure to forces of nature, sequela | BILLABLE CODE |
