In this controlled substance prosecution, defendant Dougherty was charged with ephedrine extraction. He denied knowledge of methamphetamine found in another location. The prosecutor argued that the manufacture of ephedrine was sufficient to convict. The court instructed that manufacture of a precursor drug was sufficient, and prohibited Dougherty from arguing that there was no crime if he did not know that methamphetamine was being produced. Ephedrine, although a precursor drug to methamphetamine, is not a controlled substance. Therefore, in order to convict of manufacturing a controlled substance based on ephedrine extraction, the prosecution must prove that a defendant had knowledge that methamphetamine was being manufactured. Here, the failure to instruct on that element required reversal because the error was not harmless beyond a reasonable doubt. It omitted an element of the offense from the jury’s consideration, it allowed the prosecutor to argue that ephedrine was a controlled substance, and it precluded Dougherty from presenting his defense.