Organic practices help promote healthy and sustainable soil, since natural fertilizers and pesticides must be used, requiring a greater attention to chemical balances in the soil and more proactive protection and maintenance of the local environment. This also helps prevent contamination of local water sources, by averting the spread of pesticides to other ecosystems. By switching over to organic farming, tea companies can also help lower greenhouse gas emissions by reducing the use of synthetic nitrate fertilizer. Of course, benefits to the environment also help the humans dependent on that environment, including the laborers who would otherwise be exposed to industrial chemicals. Downstream effects are notable as well, with some pollutants eventually making it to the consumer. For example, a 2012 study commissioned by Greenpeace found pesticide contamination in some tea brands.