In the realm of pharmaceuticals, activists have worked hard to compel industry to produce a registry of all clinical trials, to ensure transparency of scientific results.
In particular, prospective registration of safety testing is a good remedy to ensure transparency and to prevent suppression of findings of health or environmental risks of genetically engineered food or crops.
Regarding health or environmental risks, there is no compelling reason why the agrichemical industry should be able to keep its research findings secret. When human health or the environment is at stake, there should be a strong predisposition to transparency, and to releasing scientific results – published or not – into the public domain.
Currently, there is at no registry of scientific experiments on the health or environmental effects of genetically engineered crops. So, there is no way to discover whether the agrichemical industry has suppressed any other such experiments. (source)