In the 1970s I participated in the excavation of a rainwater cistern at the 
Thomas Wolfe House in Asheville, North Carolina. It was filled to the top 
with glass bottles (mostly Worcestershire Sauce bottles, which Mom Wolfe 
used to disguise the 'gone by' meat which she got from the butcher at a 
discount and fed to the boarders). The bottles, of course, are their own 
kind of hazard.

We made a frame of 2 x 4s from which we dangled to retrieve the contents of 
the cistern, item by item. Since then I've gone to work for the U.S. Army 
Corps of Engineers and am glad one of our site safety officers was not 
present to observe this. Don't recall that OSHA was even around.

You'll do yourself a favor to follow the advice of others and consult with 
OSHA on this. There are some serious liability problems here. Confined Space 
and excavation guidance is available from the the Corps main website at:

http://www.usace.army.mil/inet/usace-docs/eng-manuals/em385-1-1/toc.htm

One of my archaeological contractors called our safety officer the "safety 
Nazi". The training films we get to support the recommendations in this 
manual emphasize all the things it would never occur to you to even think 
of, that can happen to you and/or your crew, and I recommend that all the 
correspondents to this list take a look at this site. Pertinent to the 
subject is section 25, but there are many other items that you may recognize 
as pertinent to your job. Common sense is only the first line of defense, 
and it will only go so far.

Our archaeological contractors, like construction contractors, must submit a 
site safety plan. Even if you are not required by your contract, agency, or 
educational sponsor to do this, ask yourself: "Do I know where the nearest 
hospital is, and what the shortest route there is?". Most of us have never 
needed to know that, but the one time that you do need that information, you 
better have it. Think of explaining to the parents of your field school 
student why their child died on your watch.

End of Jeremiad.

Tim T.