Beginning December 31, 2013, it is unlawful for any person to offer for sale any deicing agent containing urea or other forms of nitrogen or phosphorus intended for application to parking lots, roadways, and sidewalks or other paved surfaces in the Commonwealth. The provisions of this section shall not (i) restrict the continued sale by retailers of any deicing agent from any existing inventories in stock on December 31, 2013, or (ii) prohibit the offer for sale or sale of any deicing agents containing urea to any municipal corporation or political subdivision for the purpose of applying such deicing agents pursuant to subsection B of § 15.2-1123.