ZFS pool hotspare replace hung

A disk in my raid z2 pool failed/is failing. It tried to replace itself with a hotspare (ata-ST18000NT001-3NF101_ZVTDW28R) but seems to have failed. I would like to remove the hot spare and manauly run the replace command. I can’t remove the disk because zfs says

cannot remove ata-ST18000NT001-3NF101_ZVTDW28R: Pool busy; removal may already be in progress

Thanks for the help.

zfs status output

      NAME                                          STATE     READ WRITE CKSUM
      storage                                       DEGRADED     0     0     0
        raidz2-0                                    ONLINE       0     0     0
          ata-WDC_WD60EFRX-68L0BN1_WD-WX52D30AVEY4  ONLINE       0     0     0
          ata-WDC_WD60EFRX-68L0BN1_WD-WX52D30AVNF8  ONLINE       0     0     0
          ata-ST6000VN0033-2EE110_ZADAG8SB          ONLINE       0     0     0
          ata-WDC_WD60EFRX-68L0BN1_WD-WX52D30AVA82  ONLINE       0     0     0
          ata-ST6000VN0033-2EE110_ZADAGFXS          ONLINE       0     0     0
          ata-ST6000VN0033-2EE110_ZADAKVHQ          ONLINE       0     0     0
        raidz2-1                                    DEGRADED     0     0     0
          ata-ST16000NM001G-2KK103_ZL21FTG0         ONLINE       0     0     0
          ata-ST16000NM001G-2KK103_ZL27RLMD         ONLINE       0     0     0
          spare-2                                   UNAVAIL     68   109    78  insufficient replicas
            ata-ST16000NM001G-2KK103_ZL28BWBD       FAULTED     25     0     0  too many errors
            ata-ST18000NT001-3NF101_ZVTDW28R        REMOVED      0     0     0
          ata-ST16000NM001G-2KK103_ZL28CETE         ONLINE       0     0     0
          ata-ST16000NE000-3UN101_ZVTEF7N0          ONLINE       0     0     0
          ata-ST16000NM001G-2KK103_ZL28JJWZ         ONLINE       0     0     0
        raidz2-2                                    ONLINE       0     0     0
          ata-ST18000NT001-3NF101_ZVTDVCF3          ONLINE       0     0     0
          ata-ST18000NT001-3NF101_ZVTDVDNR          ONLINE       0     0     0
          ata-ST18000NT001-3NF101_ZVTDVE2F          ONLINE       0     0     0
          ata-ST18000NT001-3NF101_ZVTDW28Q          ONLINE       0     0     0
          ata-ST20000NM002C-3X6103_ZXA0H7AZ         ONLINE       0     0     0
          ata-ST18000NT001-3NF101_ZVTDW2A9          ONLINE       0     0     0
        raidz2-3                                    ONLINE       0     0     0
          ata-ST8000NM0055-1RM112_ZA15VQEE          ONLINE       0     0     0
          ata-ST8000NM0055-1RM112_ZA161H3H          ONLINE       0     0     0
          ata-ST8000NM0055-1RM112_ZA161SGY          ONLINE       0     0     0
          ata-ST8000NM0055-1RM112_ZA1629FS          ONLINE       0     0     0
          ata-ST8000NM0055-1RM112_ZA162R80          ONLINE       0     0     0
          ata-ST8000VN004-2M2101_WSD80GKX           ONLINE       0     0     0
      spares
        ata-ST18000NT001-3NF101_ZVTDW28R            INUSE     currently in use