It's clear that most of the posters on this thread have not read it. I highly suggest that you do so regardless of your position on the issue.
The author (a lawyer, not a physicist) does not attempt to judge the science of the issue. He also specifically considers and discusses many of the arguments that have been set up as straw men elsewhere in the thread, e.g. "the earth has been subjected to cosmic rays for millions of years", "the objections are just the paranoid rantings of luddites and uneducated lunatics", etc.
Before I read the article I was of the opinion that opposition to LHC was simply paranoiac raving; after all the physicists at CERN understand the underlying physics, right? After I read the article I am actually moderately concerned and I hope that a court does hear a request for an injunction (I have no opinion whether an injunction is warranted but I want someone OUTSIDE the physics community to review the risk analysis done by CERN).
The author first does a really thorough job of describing the scientific literature around the proposed risks of the LHC and CERN's responses.
The second half of the paper addresses the issue of "if a request for an injunction against the LHC comes before a court, how is a judge to decide"?
The author considers and rejects both the testimony of expert witnesses (he discusses US Supreme Court criteria for judging the testimony of expert witnesses and notes that in this case there are two difficult (perhaps insurmountable) problems with expert witness testimony in this case- personal bias and testability of theories- pp55-58). The author also considers and rejects use of cost-benefit analysis which evidently is a common tool courts use to decide whether to grant an injunction (pp58-65). Instead the author poses 4 frameworks that courts could use to decide the matter - analyzing the theoretical grounding that the scientists involved used to assess risk (e.g. are the scientists basing risk on known knowns, known unknowns or unknown unknowns), analyzing for faulty scientific work (e.g. mathematical errors in calculating risk), analyzing for mistakes in risk assessment due to "credulity"- e.g. predisposition and/or groupthink (you can see that all over this thread), and analyzing for bias or negligence.
I found the table on p71 of the pdf (and the associated discussion) to be pretty damning for the dismissive position taking by LHC proponents. The bottom line is that CERN made its risk assessments and arguments for the safety of LHC, but that every time one of these arguments has been challenged, the argument was not defended, but rather a new argument was made. If it's safe, then the arguments that it's safe should be able to withstand some scrutiny- this is the empirical nature of science, right?
I am not saying that LHC is unsafe but rather that CERN hasn't reasonably proven that it is and that their behavior has raised my suspicious rather than lowering them.
Given the undesirability of the worst case scenario (destruction of the planet), it seems that there should be plausible arguments for the safety of the device that withstand moderately intense scrutiny. I'm not claiming that every nut job with a wacky theory should be able to derail such endeavors. However in this specific instance I believe that there are plausible concerns that have not been adequately addressed.
I'm not going to drill into further details of the paper but as of this writing, the author of the paper had addressed the arguments proposed in every concern (or dismissal) that I've read in this /. thread at +3 or higher moderation.