As defined by Nick Bostrom, an information hazard is “a risk that arises from the dissemination or the potential dissemination of (true) information that may cause harm or enable some agent to cause harm.”
In his work, Bostrom has categorized a great number of information hazards. One example is “data hazards”, which concern dissemination of data that could do harm if put in the wrong hands, such as data on how to produce weapons of mass destruction.
An important ethical and practical issue is how information hazards should be treated. To what extent should people suppress acquisition and dissemination of information which may cause harm? The answer to this question both depends on one’s moral views - for instance, whether new knowledge is good in itself, or whether it is wrong to restrict personal liberty - and on one’s empirical views of what the outcome of such suppression is likely to be.
Bostrom, Nick. “Information Hazards”. Review of Contemporary Philosophy, Vol. 10 (2011).
Kitcher, Philip. 2001. Truth and Democracy.