Field testing of genetically engineered microorganisms.

The first approved field releases of microorganisms genetically altered in the laboratory have been initiated in the past several years. While most introductions have been carried out in the United States, several tests have also occurred in the United Kingdom and Australia. Although such releases remain controversial in some areas, these pioneering studies have provided significant insight into the environmental behavior and relative safety of applying these microbes in a well-planned and carefully monitored program.