Five corporations and a trade group representing food manufacturers have largely financed efforts to defeat Initiative 522, raising $17.2 million so far, according to the latest campaign finance reports. Other advocates worry about potential environmental harm from genetically modified crops, such as cross-contamination with non-GMO crops, while some object to increased corporate control of food. In TV ads featuring a farmer and a former state agriculture director, opponents say the measure creates misinformation by exempting many food products and poses unnecessary burdens for farmers and food manufacturers. Genetically modified crops come from seeds that are engineered to resist insecticides and herbicides, add nutritional benefits or improve crop yields. Most GMO crops such as field corn and soybean are used for animal feed or as ingredients in processed foods including breakfast cereal, potato chips, baked goods and sodas. The Yes on 522 campaign has steered cleared of raising safety issues, but the initiative text says mixing plant, animal and other genes "can lead to adverse health or environmental consequences." The World Health Organization has said GMO foods currently available on the international market "are not likely to present risks for human health" and no ill health effects have resulted. Major agricultural groups including the Washington State Farm Bureau, Washington Association of Wheat Growers and Washington State Dairy Federation have lined up against the measure, while the United Farm Workers, the Washington State Nurses Association and Washington Conservation Voters are in support.