Somewhere I learned that kitty litter uses specific clay as its main ingredient. This clay is strip mined. Strip-mining, according to Webster's College Dictionary, is a mine that is worked from the earth's surface by the stripping away of overlying material. So everything from the canopy down through the soil horizons are removed. After the mining process is completed the mine is often abandoned without any environmental restoration applied. Typically, strip mining is used with coal mining.
After discovering this, I researched other environmental issues with kitty litter; and discovered that the sodium bentonite is a hazardous chemical that naturally occurs within the clay. Sodium bentonite expands into a hard mass when wet. Makes things easier when cleaning, but not so healthy for my kitty or myself because when inhaled the clay expands in the lungs. This can cause asthma and other lung complications. The pads on their paws can develop sores. And ingestion from the cleaning of the paws isn't all that healthy either. (http://www.greenlivingonline.com/)
Silica based litters absorb odors and moisture. It's easy to inhale when the litter is disturbed. Lung cancer, bronchitis, and TB in humans have all been linked to silica. Cats have been known to develop a fatal form of pulmonary TB and silico-TB. No wonder pregnant women aren't supposed to be handling kitty litter, I don't currently want to either.
Aside from all of the chemical hazards and side effects of kitty litter, another environmental issue is that it's not biodegradable because clay is in its basic form. Two million tons of kitty litter is sold every year, most of that is going to the landfill.
Now that I've been thoroughly depressed by all of this info, I've been looking for the solutions. I don't entirely trust the "flush it" kitty litters and I'm renting, ergo any chance of the toilet malfunctioning is a no go. Due to this decision, a compromise has been made. Cut out the harsh chemicals but still send the waste to the landfill.
So for the past few weeks I've been using Fresh & Natural: Scooping Clumping Cat Litter. Their mining process consists of nature restoration following the clay harvesting. The nature restoration consists of topsoil replacement and is reseeded with native pasture grass. The packaging is recyclable. The company has definitely made a lot of contributions to the environment and has won the Excellence for Mining Reclamation Award, given to them by the Wyoming Department of Environmental Quality.
The litter uses dehydrating crystals and flower extracts for odor control. However, its main ingredient is sodium bentonite. My flaw derived from too little information in the store in combination with not enough prior research. So I'm back to the drawing board.