S. Walter,

you are about to embark on what is called confined space entry.  there are a host of safety regulations for this type of work, some of which were mentioned by David.  "bad air" can be a life-threatening hazard.  You would do well to contact OSHA or even your local fire company about safety requirements for this work.

Ed
-------------- Original message -------------- 
From: David_Hayes_STX <[log in to unmask]> 

> Message text written by HISTORICAL ARCHAEOLOGY 
> > 
> July 17, 2006 
> 
> Hello Histarchers, 
> 
> I am going to be going into a working cistern that was built in 1900. It 
> has a flat floor. Access is wide enough at the top for careful entry. 
> Currently there is about 3 feet of water in it that we are pumping out. I 
> will be wearing a hardhat, rubber gloves and rubber boots. We plan to 
> scoop out any muck and examine the interior while in there. 
> 
> Has anyone else done this? 
> Any safety suggestions for me? 
> Anything else I should look for? 
> 
> Thanks, 
> 
> S. Walter 
> < 
> 
> Hello 
> 
> Around here we have businesses that clean cisterns, since we still use them 
> for household water. 
> 
> Safety is paramount. 
> I would not worry about bugs IF THE WATER IS STILL BEING used for human 
> drinking or showers, otherwise it is by definition suspect. Often with a 
> sump pump you can get the smalll stuff with the water. A lot of this is 
> organics like pollen. 
> 
> Lighting in the cistern. No incandent bulbs heat. All electrical equipment 
> on site by protected by working GFI breakers. 
> 
> Short times in cistern for the work crew: heat & CO2. You can rent fans 
> with ducts to put air in. 
> 
> At least as many people outside as inside. 
> 
> Look at the interior sealant to see repairs. 
> 
> 
> David Hayes RPA 
> St. Croix, Virgin Islands