The RSPO have developed a set of environmental and social criteria which companies must comply with in order to produce Certified Sustainable Palm Oil (CSPO). When they are properly applied, these criteria can help to minimize negative impacts.
One of the most important RSPO criteria states no primary forests or areas with high biodiversity (e.g. endangered species) or fragile ecosystems, or areas which are fundamental to meeting basic or traditional cultural needs of local communities (high conservation value areas), can be cleared.
Other RSPO principles stipulate a significantly reduced use of pesticides and fires; fair treatment of workers according to local and international labour rights standards, and the need to inform and consult with local communities before the development of new plantations on their land. You can learn more about RSPO's Principles and Criteria here.