Prior to the adoption of a substantive rule, opportunity for a public hearing will be granted by the Texas Department of Protective and Regulatory Services if requested by at least 25 persons, a governmental subdivision or agency, or by an association of at least 25 members, within 30 days of the effective date of notice established by publication of the proposed rule in the Texas Register. A public hearing will also be held by the department when directed by the Texas Board of Protective and Regulatory Services or the executive director of the Texas Department of Protective and Regulatory Services.