Before petitioners seeking a writ of prohibition challenged the Department of Environmental Regulation’s jurisdiction, pursuant to Fla.Admin.Code Rule 17-1.60, to review interim orders of hearing officers in proceedings under Section 120.57, Florida Statutes, 1977, they challenged the rule in Section 120.56 proceedings. The hearing officer found Rule 17-1.60 to be invalid. Therefore the issue of this petition for writ of prohibition is now moot. We of course are not asked in this proceeding, nor do we decide, the appropriateness of the hearing officer’s order entered in another ease as to the validity of the rule.

The petition for writ of prohibition is DENIED.