Would it violate deontological ethics for me to build a factory in a poor country in which workers are knowlingly exposed to a small risk of death?

You can't treat "deontological ethics" as if that phrase gives specific rules. It refers to an entire class of ethical systems.

However, you can look at various real world systems and cases to make predictions about how your factory would be received. It is common in a situation like this for people to believe that if you know that there is a risk, and you do not tell people about the risk, then you are morally (and often legally) negligent. If you do tell people of the risk, and then people get hurt, people will find you morally (and often legally) negligent, because most people actually hold teleological ethic beliefs on an emotional level.

tl;dr -- neither of these cases necessarily violate deontological ethical systems. Get a good lawyer anyway.

EDIT: Fixed typo.