This guest post is by Stephen Tan, who practices environmental law with Cascadia Law Group and serves on the Board of Trustees of PCC Natural Markets, a leading supporter of an initiative that would require labeling most genetically modified foods in Washington State.

Washington State voters will soon decide whether food produced through genetic engineering must be labeled. Initiative 522 opponents, the chemical companies that sell genetically engineered (GE) seeds and the processed food companies that manufacture and sell GE foods, insist that GE foods have been proven safe and that labeling therefore isn't necessary. But human health effects haven't been fully studied, and GE foods have other significant adverse effects on our environment and our economy. Consumers should be alerted to and consider these impacts when making decisions about their food.

Contrary to industry claims, there is no scientific consensus that GE foods are safe. The Food and Drug Administration neither conducts nor requires independent safety assessments of GE foods, so market approval for GE crops are based on industry research alone. Most of this research examines only nutritional equivalence—calorie, fat, and vitamin content, for example—not toxicity to consumers. The Washington State Academy of Sciences, a panel created by the State Legislature to provide unbiased analysis of issues important to the State, recently recommended "long-term, thorough, and case-by-case scientific studies" for GE plants. WSAS also calls for better testing protocols. Until reliable data from improved testing are available, it cannot be claimed that GE foods pose no risk to human health.

Possible health impacts aside, GE foods have significant environmental, economic, and social impacts that consumers should consider.

Twenty years ago, we were promised that genetic engineering would confer drought tolerance, improve the nutritional profile of our food, increase crop yields, and reduce farmers' reliance on chemical inputs. Not one of these benefits has materialized. No GE seed currently on the market offers better drought tolerance or nutrition than existing varieties. The Union of Concerned Scientists concluded in 2009 that traditional seed breeding should be "solely credited" for any increases in yields over the last century. And a peer-reviewed study by a WSU researcher concluded that GE crops have increased herbicide use since 1996 by 400 million pounds.

Virtually all GE crops now available either produce the pesticide Bt toxin or withstand the application of glyphosate, a broad-spectrum systemic herbicide sold as Roundup. The overuse of these crops, and the industrial farming practices they both represent and promote, have damaged the environment. They have harmed pollinators and wildlife, reduced biodiversity, compromised soil health, and contaminated groundwater, streams, and rivers. They have also caused resistant pest and weed species to evolve, forcing farmers to resort to the very toxic compounds genetic engineering was supposed to make unnecessary.

GE crops have also harmed our economy. This past spring, a farmer in Oregon discovered a strain of experimental GE wheat growing in his fields. Although that particular GE wheat strain had been field tested in 16 states, no authorized testing had been conducted in Oregon since 2001, and Monsanto had by 2004 abandoned its plans to seek approval of it. The Oregon farmer's unexpected and still unexplained discovery caused Japan, Korea, and Taiwan to immediately suspend imports of soft wheat from the Pacific Northwest. This was a severe blow to Oregon and Washington wheat farmers, who export 90 percent of their crops, mostly to Asia.

Concerns over possible contamination are justified by recent history. In 2000, a strain of GE corn approved for use only as animal feed because it was found to trigger allergies in some people was discovered in commercially-produced taco shells. The resulting product recalls in North America, Europe, and Asia cost the food industry an estimated $1 billion. In 2007, contamination of rice by a GE strain caused U.S. rice exports to plunge 20 percent from the previous year. And in 2009, an unapproved GE flax seed contaminated Canadian supplies, causing the collapse of Canada's flax export market to Europe.

Not even farmers themselves have benefited from genetic engineering. In recent years, the chemical companies that manufacture GE seeds have moved aggressively to buy small seed companies. Their consolidation of the seed industry has, predictably, reduced the availability of seed varieties, dramatically increased the cost of GE seeds, and triggered a federal investigation into anti-competitive pricing and monopolistic practices. In 2002, the U.S. Department of Agriculture concluded that the farm-level economic impacts of GE agriculture were “mixed or even negative.”

Finally, labeling is a social justice issue. Everyone should have the right to be informed about and the freedom to choose their food. The existing voluntary labeling system may serve shoppers with ready access to organic and other non-GE foods. For many, however, it is inadequate, especially since certain federal aid programs prohibit spending on organics, including such staples as baby food and formula.

With total contributions of over $21 million and counting, opponents of I-522 have mounted the most expensive initiative campaign in state history. As it turns out, these companies have good reason to resist calls to label their products. There's much we don't yet know about GE foods, and what we do know about their adverse impacts on the environment, our economy, and social equity should concern us. Labeling of GE foods will allow all Washingtonians to make better informed decisions for themselves, for their families, and for the overall health of our state. Washington citizens should vote yes on I-522.