It has many of the characteristics of nuclear fallout - disperses throughout the entire environment, the whole body, where it may take decades to cause disease.
Probably we didn't realize how dangerous it was because it's not apparent until it becomes persistent in the environment. With a high enough dose radiation sickens you immediately, and does all kinds of other weird things, we realized it was dangerous not long after it was discovered. (Yes, I know it took decades for the general public to catch up to the science.)
This shit needs to be removed from our presence starting yesterday. We need clear guidelines for people on which types of food and drink container to avoid, and strict regulations on the producers to minimize the amount of microplastics in the food. Probably also HEPA filters in our homes, cars, and offices, given that you breathe it in too.