Inapplicability of prohibition on local preemption, when

The provisions of subsection 6 of section 319.342 in regard to the provisions of sections 319.300 to 319.342 or any rule promulgated by the state fire marshal thereunder shall not apply to an ordinance, order, permit, or regulation in effect as of January 1, 2007, which regulates the use of explosives at the site of a quarry in any county with a charter form of government and with more than two hundred fifty thousand but fewer than three hundred fifty thousand inhabitants. For purposes of this section, quarry shall include any place where rock, ore, stone, or similar materials are excavated for sale or off-premises use. A quarry shall not include the removal or relocation of rock, stone, or earth incidental to the construction of residential, commercial, or industrial buildings. Nothing in this section shall be construed to exempt any person loading or firing explosives in any county governed by this section from meeting the licensing requirements of section 319.306 and paying licensing fees under that section. Neither shall this section be construed to exempt any person using explosives in any county defined by this section from registering with and reporting to the division of fire safety under section 319.318 and paying all registration and reporting fees under that section.