"Radioactive materials for example Plutonium and Tritium. Note that this
item has a negative trade value, in other words, you have to pay for
someone to take it off your hands. Some make a living out of being paid to
take this waste away and deliver it to reprocessing plants (ie, anywhere
that has Radioactives as a major import). More unscrupulous and
irresponsible characters will prefer to jettison it instead, risking
prosecution. This is a highly illegal practice and locals are usually
vehemently opposed to this act. Police often don't bother with questions
but deal with you there and then, as this not only saves on police time but
court fees as well."
These items carry a negative price, so it is often profitable to buy some radioactives and dump them in outer space, especially if you have space free in the hold. It is also worth noticing that the "illegal" price is LESS than the price in places where radioactives are legal.