I didn't find anything on him when I searched on Google using "Peter Hansen civil engineer New York City", though I only checked the first 10 pages of links.
I had previously searched under "Peter Hansen New York City". I know this Peter Hansen is not the actor, the law professor, or the guy with a ballet company. If he is this Peter Hansen, however, it might explain a lot.
This is G o o g l e's cache of http://www.un.org/unrwa/email/.
This is G o o g l e's cache of http://www.palestine-un.org/news/oct96_high.html.
This is G o o g l e's cache of http://www.refugees.org/world/ngo_directory.htm.
This is G o o g l e's cache of http://www.hri.org/news/world/undh/2001/01-04-19.undh.html.
While it seems unlikely they'd be the same person, how much license is taken with the phrase "a civil engineer employed by New York City government"? Is he a lowly full time 9-5er borrowing against his 401K or his home equity, or is he some consultant or board member showing up for a meeting every so often?