There is a "paint"  that is used on wood floors (and other places)
that will seal in fumes, formaldehyde, and other substances that cause
allergenic reactions. Named: Crystal-lite. I believe it's
water-soluble.

I'm fairly sure about the "lite" though it may be "light".
I am sure about the hyphen - - I located 2 or 3 catalog stores for the
product through Google earlier and discovered that without the hyphen
there is a sugar substitute with that name.

Where can this be purchased in the US?

Northptr1, 

This sounds like a great idea: I do woodwork and am always on the
lookout for alternatives to solvent-based finishes.

I have looked extensively but cannot find any Web references for
non-toxic wood finishes under the following brand names:

   "Crystal-Lite"
   "Crystal Lite"
   "Crystal-Light"
   "Crystal Light"
 
However, I think the wood finish you are looking for is actually named
"Crystal Shield" or "Crystal Aire", and there are several references
to these products on the Web.

Crystal Shield is a clear, water-soluble, acrylic-based, non-toxic
sealant designed for use on wood floors, furniture, and cabinets. A
description of Crystal Shield can be read at Nirvana Safe Haven, an
online store specializing in non-toxic products:

   Nirvana Safe Haven
   Non-toxic wood floor and furniture sealants and finishes
   http://www.nontoxic.com/nontoxic/crystalshield.html

"Crystal Shield makes all other hardwood floor finishes obsolete! This
rugged, durable floor finish and protectant suitable for the demanding
service of hardwood floors in homes, auditoriums and gymnasiums is the
best. No need for toxic urethanes and varnishes. Protects, beautifies,
resists scratching, abrading, peeling and chipping. Apply with
conventional mop, lambs wool applicator, or paint pads or spray. Dries
to the touch in only two hours. No toxic fumes! Water clean up. Do
allow for drying time between coats. Finishes are in matte and gloss."

This same web page mentions another sealant called "Crystal Aire" that
can be used:

"... everywhere where resins or fumes are problematic. Protects and
beautifies while blocking out toxic fumes from any clean, dry,
non-waxy surface including wood furniture and of course toxic particle
board. Crystal Aire can block the effects of latex and oil paint, wall
paper, and be used over urethane and lacquer finishes. It can be
applied to metal and ceramic tile."

Here is full contact information for Nirvana Safe Haven:

   Nirvana Safe Haven
   3441 Golden Rain Road, Suite 3
   Walnut Creek, CA  94595
   Tel: 1-800-968-9355, 1-925-472-8863
   Fax: 1-925-938-9019 
   Email: daliya@nontoxic.com
   Web: http://www.nontoxic.com

I called them toll-free and spoke with the owner, Daliya Robson. A
consultant on non-toxic finishes and products, she thinks highly of
Crystal Shield/Aire finishes, but has had difficulty keeping them in
stock due to their popularity. For dealers in your area, she suggested
that you also contact their manufacturer, Pace Chem Industries (see
References below).

Nirvana carries another line of non-toxic finishes that may also work
for you:

   Nirvana Safe Haven
   AFM SafeCoat Protective Sealers
   http://www.nontoxic.com/nontoxicpaints/protectivesealants.html

In particular, Daliya recommended their "Safecoat Polyureseal BP"
product.

The following environmental newsletter favorably mentions the
non-toxic wood finishes manufactured by Pace Chem and AFM:

   Watershed Sentinel, Feb/Mar 2001
   The Unvarnished Truth
   http://www.rfu.org/ws111.htm

"Matt[*] recommends two brands of water-based floor finishes, Crystal
Shield by Pace Chem and Safecoat Polyureseal BP by AFM. Before making
a choice, it would be wise to confer with a knowledgeable salesperson
and see some samples. Other brands of water-based finishes are
available, but Matt feels that the two companies whose products he
carries have designed their products from the bottom up to be as low
in toxicity as possible..."

*This refers to Matt Freeman-Gleason of the Environmental Home Center
in Seattle, Washington (see References below).

I believe that one of these products will meet your needs. 

Thank you,
Huntsman


References -

Wood finish manufacturers mentioned above. Contact them for additional
product and dealer information:

   Pace Chem Industries, Inc.
   "Crystal Shield" & "Crystal Aire" finishes
   156 North Garden Street 
   Ventura, CA  93001
   Tel: 1-800-350-2912

   AFM Enterprises
   "Safecoat" finishes
   350 West Ash St., Suite 700
   San Diego, CA 92101
   Tel: 1-800-239-0321
   Web: http://www.afmsafecoat.com/

Here is another online retailer for Pace Chem and AFM products:

   Green Home
   Care2 Store
   http://care2.greenhome.com/products/prodpagehoi-aas.html

Resources for "Green" building materials:

   Environmental Home Center
   Green Building Materials
   http://www.environmentalhomecenter.com/

   Sustainable Building Sourcebook
   Table of Contents
   www.greenbuilder.com/sourcebook/ 

   Sustainable Building Sourcebook
   Paints, Finishes, and Adhesives
   http://www.greenbuilder.com/sourcebook/FinishesAdhesives.html


Search Terms & Google Results - 

   organic paints stains 
   ://www.google.com/search?sourceid=navclient&q=organic+paints+stains

   non-toxic floor finish "Crystal Shield"
   ://www.google.com/search?sourceid=navclient&q=non%2Dtoxic+floor+finish+%22Crystal+Shield%22

   green building materials
   ://www.google.com/search?sourceid=navclient&q=green+building+materials

First class answer.
Complete, found my error in the naming (whichIhad just uncovered also).
Thorough. As well as friendly.  Many thanks. PNorthrup@Comcast.net