Versions of s. 50(7)(c)

if within five years of the time the article was first purchased or, if imported, released under the Customs Act for a use rendering the purchase or release exempt from tax imposed under this Part and Part III or either of those Parts, the article is applied to any use, other than of a casual nature, for which it could not, at the time of such first purchase, have been purchased or released exempt from the tax, the article shall be deemed to have been sold at the time of its first application to that use and tax imposed under this Part and Part III or either of those Parts, shall be imposed, levied and collected at the time of its first application to that use,