When meth was first manufactured in the 1970s, the recipe called for lots of heavy metals. Contamination throughout the site was more common. The next cooking method used lots of solvents and caustic material, which would also be harmful, but was more likely to evaporate before it caused much trouble. One process calls for the cook to spray ether onto the oil that rises to the top at the end of cooking process. One guy didn't want to wait for the ether to work, so he put the whole thing into the oven.
Cooking is started by running an electric charge from a lithium battery through the mixture.
Though the ammonia can be a problem, this is much better for the environment because everything evaporates so quickly. But, it is much harder on law enforcement agencies. The method can yield a batch of meth in less than an hour, as opposed to several days with the older methods, making it much harder to catch the criminals. A cleanup where the newer method is used rarely requires more than the removal of debris. He cautioned that none of the material is ever stored at company offices, but is sent directly to a landfill.