Organic farming, as defined in the final rule establishing the U.S Department of Agriculture (USDA) National Organic Program (NOP), is "a production system that is managed in accordance with the [Organic Foods Production] Act and regulations ... to respond to site-specific conditions by integrating cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity." This definition indicates that organic agriculture is both an approach to food production based on biological methods that avoid the use of synthetic crop or livestock production inputs (spelled out in detail in the December 2000 rule), and a broadly defined philosophical approach to farming that puts value on resource efficiency and ecological harmony. Interest in organic farming migrated from Europe to the United States in the early 1900s. Beginning in the 1950s, as the U.S. public became more concerned about the potential adverse environmental and public health effects of agricultural chemicals and so-called "factory farming" methods, private research organizations began to conduct scientific investigations into non-chemical and non-intensive farming techniques, and a small but slowly increasing number of farmers began to adopt organic production practices. Except for a brief period from about 1978 to 1981, USDA did not conduct any activities in support of organic agriculture until OFPA required the Department to begin rulemaking to establish the National Organic Program in 1990. The annual rate of market growth for organic foods and other products has remained around the 20% rate it achieved beginning in 1990, although analysts generally expect it to moderate over the next decade. The Organic Trade Association's (OTA's) 2007 Manufacturer Survey determined that sales of organic food products were $16.7 million in 2006, or 2.8% of total U.S. retail food sales. About 38% of organic foods are sold through conventional retailers, 44% through natural food stores, and 16% through farmers' markets, mass merchandisers and club stores, restaurants, exports, and other marketing channels. Various sources of export data estimated U.S. exports of organic foods at between $125 million and $300 million in the 2000-2002 period. The biggest export market is Canada; other major markets are Japan, the European Union, and other countries in Asia. The OTA 2007 Manufacturer Survey reported that $938 million in nonfood organic product sales occurred in 2006. The fastest-growing categories were organic supplements, personal care products, flowers, pet foods, and fibers. According to USDA's Economic Research Service (ERS), 2005 was the first year that all 50 states reported having some certified organic farmland. Nationwide, the number of acres of certified organic cropland and pasture/rangeland was 4 million in 2005. ERS estimated that in 2004 the number of certified operations that process and distribute organic products was just over 3,000. Fresh produce is the largest sector of the organic industry, with California having the greatest number of acres devoted to organic fruit and vegetable production (see Figure 1 ). Other states leading in certified organic crop acreage are Washington, Oregon, North Dakota, Minnesota, Wisconsin, Montana, and Iowa. California, Texas, Alaska, and Montana have the most acreage of organic pasture for livestock. In the Northeast, Southeast, and Upper Midwest, small-scale growers of organic fruits, vegetables, herbs, and flowers are a significant component of individual states' agriculture industries. The high growth rate in sales of organic products can be attributed in part to the higher prices that organic producers and processors receive for their products, according to ERS. Agency economists speculate that part of the price premium may be due to higher production costs and to higher demand relative to supply. For the 2000-2004 period (the most recent data available), the annual average farmgate price premiums for fresh organic broccoli and carrots fluctuated from 75% to 133% above the prices of conventionally grown broccoli and carrots, according to ERS. Price premiums for the two vegetables at the wholesale level never went below 125% in the same period. The ERS study goes on to say that: Laws of supply and demand, however, make it unlikely that price premiums contributing to higher profits and market growth can coexist over the long run: as long as higher profits exist, new suppliers will enter the market, and once market supply increases faster than demand, price premiums and the commensurate level of higher profits are likely to decline.... Many organic industry participants and observers believe that the price premiums ... need to decrease if organic foods are to penetrate much beyond the 2- to 3-percent level into the mainstream. The consumer studies that ERS reviewed did not permit any clear estimate of future demand for organic products. The studies showed that price, size, packaging, appearance, and concerns about health and nutrition, taste, food safety, and the environment all play varying roles in consumer decisions to buy organic food. Surveys on race, ethnicity, and income levels showed significant diversity. Congress passed the Organic Foods Production Act (OFPA) of 1990 (Title 21 of P.L. 101-624 , the Food, Agriculture, Conservation, and Trade Act of 1990; the 1990 farm bill) with widespread support from organic industry groups, the National Association of State Departments of Agriculture, and other farm and consumer groups. The organic industry petitioned Congress to draft the act in the late 1980s, after it had been frustrated in its attempts to come to an internal consensus on production and certification standards. The industry maintained that federal standards would reduce consumer confusion over the many different state and private standards then in use, and would promote confidence in the integrity of organic products over the long term. Manufacturers of multi-ingredient organic food products stated that uniform standards would facilitate labeling. Others held that regulations would help the organic industry expand product lines and increase marketing opportunities. Industry analysts asserted that a consistent U.S. organic standard would facilitate access to a potentially lucrative international organic market. The Organic Foods Production Act of 1990 authorized a National Organic Program to be administered by USDA's Agricultural Marketing Service (AMS). The act established a 15-member National Organic Standards Board (NOSB) to "assist in the development of standards for substances to be used in organic production" (referred to as the "National List") and to "provide recommendations to the Secretary regarding implementation." Under the program, producers, processors and handlers who wish to market their products as organic are required to follow production practices as spelled out in detail in regulations (7 CFR 205). USDA accredits private and state certification agents, who visit producers, processors, and handlers to certify that their operations abide by the standards; they conduct annual reviews to verify continued compliance. It is illegal for anyone to use the word "organic" on a product if it does not meet the standards set in the law and regulations. The presence of the "USDA Organic" seal on a product means it is 95% or more organic. Labels on products having 70% to 95% organic content can say "made with organic (specified ingredients or food groups)," but cannot carry the seal. Foreign organic producers and handlers wishing to export products to the United States may be certified by a USDA-accredited certification agent in their own country, if there is one; or USDA may accept certification by agents accredited by a foreign government; or, USDA may negotiate an equivalency agreement with another nation's organic program. The regulations under the OFPA are intended to set uniform minimum standards for organic production. States may adopt additional requirements after review and approval by USDA. Furthermore, private organic organizations are permitted to affix their own labels in addition to the USDA label, indicating that the product meets their standards as well as the national ones. The private label may indicate only that the organization's standards are in addition to (but not superior to) the national standards. AMS reviews certification agents for re-accreditation every five years. AMS has the authority to revoke or suspend a producer's certification or an agent's accreditation if a satisfactory solution to a program violation cannot be found. The NOP final rule became effective on February 21, 2001; the program itself became fully operational on October 21, 2002. In the first step toward implementation, USDA accredited private and state certification agents, who in turn began to certify organic producers and handlers according to the standards found in 7 CFR 205. After October 21, 2002, all products sold as organic had to be in compliance with the regulations and carry the "USDA Organic" seal. In January 2005 a newspaper article about a Colorado organic dairy operation shed light on a major controversy within the organic industry and certain consumer groups. The article focused on a 5,300-cow organic farm where the animals were fed almost exclusively on grain and allowed outdoors into a feedlot for air and exercise. The NOP regulation at the core of the dispute is 7 CFR 205.239(a)(1-2): "The producer of an organic livestock operation must establish and maintain livestock living conditions which accommodate the health and natural behavior of animals, including (1) Access to the outdoors, shade, shelter, exercise areas, fresh air, and direct sunlight suitable to the species, its stage of production, the climate, and the environment; (2) Access to pasture for ruminants[.]" The news article cited organic dairy producers who argued that the regulation means that organic cattle must get some of their nutrition, as well as fresh air and exercise, from grazing on pasture. The Colorado operator maintained that his animals have outdoor access, but that in an arid state like Colorado, providing sufficient pasturage for all his cows to graze would be an insurmountable requirement. This issue illustrates an underlying tension within the organic industry. The existence of regulatory standards for organic production and processing has allowed more conventional food companies to create organic product lines and enter the market. Some of the older (and generally smaller) companies in the industry hold that organic farming practices are an integral part of the meaning of the term "organic," particularly with respect to standards for the treatment and feeding of livestock.