Non-English literature: should we check for prior work?
Is it safe to ignore non-English publications in some fields like computer science, chemistry or physics? 


I would try my best to not ignore. If you are citing a paper that has cited a non english journal, I would read the citation to see if its relevant to my paper. Translation tools, although not always accurate, would give you a sense what the paper is talking about. 
Maybe this article can answer your question to an extent. 

http://www.ete-online.com/content/5/1/12