When looking to refinish your hardwood floor, the main thing to consider is an environmentally friendly hardwood finish. Most commercial finishes are solvent- and lacquer-based, which are terrible pollutants of air quality. However, over the last few decades natural and water-based finishes have become available, and the quality of these finishes have greatly improved in recent years, bringing them up to par with the standard, yet harmful, solvent- and lacquer-based finishes.

The first step in refinishing your hardwood floor is to remove the current layer of finish. It is important not to use paint thinner for this job, as paint thinners pollute the air and are bad for your health. A better, more eco-friendly and healthy option is to sand down the current layer of finish. This can be done with a floor polisher--attach a 100-grit abrasive screen to the plastic wheel of the floor polisher, and move across the floor with the grain of the wood, in an overlapping pattern. Make sure to remove all dust and dirt before applying any primer or stain--first sweep, then vacuum, dust, and vacuum again. Follow by wiping the floor down with a soft cloth that has been slightly dampened with mineral spirits, a mild solvent, to remove any last dust. Now you are ready to apply the wood finish.

However, if you prefer using paint thinner to sanding, choose one that is methylene chloride-free. Some options include Bio Wash, 3m Safest Stripper, Ready-Strip Pro, and Citrus Strip. But remember that even these can be harmful!

Note: Be sure to discard any paint chips as hazardous waste, especially if your floor was finished before 1980, as it will likely contain lead.

Traditional finishes leech chemicals into the air for up to five years after they have been used.  Instead of these traditional finishes, choose one that is natural or water-based and has a no- or low-VOC level.  Also be sure to avoid ingredients such as petroleum distillates, formaldehyde, metals, and waxy finishes. Your local hardware store may not have a large selection of environmentally friendly finishes--be sure to ask an employee for the store's options, and don't be afraid to ask them to special order a finish. Also, you can choose from a larger variety of finishes by ordering online.

There are some common qualms about water-based wood finishes, but many of the issues have been solved with recent improvement to the finishes, and there are simple solutions to other problems you may face.

Common Problems and Solutions:

Water-based finishes are more expensive than traditional lacquer- and solvent-based alternatives.

Water-based coatings often don't have the same warm appearance of lacquer- and solvent-based coats. Add a small amount of water-soluble dye color to give it the same appearance.

Recently the quality of the adhesion and grain-raising effect have both improved in water-based formulas.

Newer water-based formulas are more durable, and live up to the standard that solvent-based coats have set. This is especially seen in water-based UV-cured materials, which meet performance expectations.

The Green Guide is a good resource for a comprehensive article on the benefits of environmentally friendly wood finishes.

Some good finishes to look for: BonaKemi--the only hardwood flooring system that is Green Guard certified for indoor air quality, Tried and True Wood Finishes, BioShield, Auro Paints, AFM, Envirolast, and ZVOC.