The Bureau of Land Management Web site has been shut down for the last two weeks because of what officials vaguely describe as ”security concerns.”The decision to shut down the Web site was made by top agency officials in Washington, D.C., said John ”J.C.” Hanf, natural resource staff supervisor for the BLM in Prineville.”The bureau had some security issues,” he said. ”And we’re not sure how those security issues were identified.”Hanf said he does not know whether anyone hacked into the agency’s Web site. He said he has not heard whether political, legal or other concerns prompted the decision to shut down the Web site.While the agency is offline, people will not be able to access www.boaterpass.com, a BLM-operated site that enables people to buy Deschutes River boating passes.People who try to access that site will be directed to an alternate site, containing a list of vendors in Central Oregon. Passes may be purchased in person at any of the offices and businesses listed.”When they get everything resolved, then we’ll be back up and running,” Hanf said. ”But I don’t know when that will be.”