Director liability: unpaid GST tax may be joint and several unless absence of gross neglect is proved; conversion exemption limited. Section 89 makes every person who was a director of a private company during the relevant period jointly and severally liable for unpaid tax, interest or penalty where recovery from the company is not possible, unless the director proves non-recovery was not due to gross neglect, misfeasance or breach of duty. If the company converts to a public company and recovery could not be effected before conversion, subsection (1) does not apply to such directors for those amounts, but any personal penalty on a director remains unaffected.