The protective glass shield could not block off 100% of the surrounding radiation. The glass could block the radioactive particles in the air, the effects from the radioactive clouds, and radiation-contaminated creatures, etc. However, no matter what methods the residents tried, they were unable to decontaminate the soil under their feet.
The residents of Garden of Eden could not eat soil grown crops, instead, they had to ration their crops which were grown via aeroponics. It took twenty years of research before the "Crop Sticky Cloning Technique" was developed. It was only then that sufficient food was produced to support the city. In the past, women who haven’t had children could never have a full meal.
