Interestingly, produce that is grown overseas is subject to much closer scrutiny than things like cookies, powdered drinks, and frozen foods. The FDA requires random sampling of all produce that comes into the US for certain chemical signatures. If found, the entire shipment is refused. No such mechanism is in place for "non produce" items. Those Oreo looking cookies made in India? Sure! Come on in!
What about seafood?
There is a lot of seafood produced overseas - especially in Asiatic countries: China, Vietnam, and Thailand specifically. There currently are no standards for "organic" seafood, and the FDA does not regulate seafood farms overseas. There is currently no way to ensure that the fish you are eating were raised in a wholesome manner, were fed a healthy diet, or were handled appropriately. In my non-scientific opinion, it is in your best interests not to buy seafood raised overseas.
Examine packages of frozen fish at the store - and across the board, you are going to see "Product of China" in very small print on the back of these packages. Recently, several large scale fish farms outside of Bejing were caught feeding excessive antibiotics and human contraceptive medicines to fish under their care. Why? The Chinese discovered that fish fed birth control pills matured at a much faster rate than untainted fish - they could be harvested several months earlier: more profit.Luckily for us, these farms were NOT exporting their fish.
What can you do?
In the US, seafood needs to be labeled with its country of origin. Start looking for seafood that is raised and distributed in the US. You can be more certain that it was raised in a wholesome manner and doesn't contain heavy metals, toxins, or chemical traces.
Are foods produced overseas safe to eat? I would say - as a generalization - that foods produced in developed countries and imported to the US and other countries are safe to eat.