Poison in the Garden

The Environmental Protection Agency (EPA) announced recently that it is investigating an ingredient commonly found in potting soil. Vermiculite-a small chip found in many potting mixes-is a new wonder chemical in gardens around the country. Now the EPA wonders if this wonder chemical could kill, or poison.

Vermiculite is a naturally occurring mineral in soil. It is known for holding moisture and nutrients, which is why it helps so many gardens grow and flourish. It is also an excellent way to aerate heavy soil.

The problem is that the EPA has received reports that there are dangerous, potentially fatal, asbestos fibers in some of the vermiculite products. They are investigating these reports and testing products that contain the potentially deadly mineral.

Worries began this winter. They were sparked by a series of articles in The Seattle Post-Intelligencer. The articles were about a vermiculite mine in Libby, Montana owned by W. R. Grace. While the mine is now closed, the newspaper reported that the ore at the mine was tainted with toxic asbestos called tremolite.

More than 300 miners and their family members had contracted diseases allegedly linked to the asbestos mine. The diseases included asbestosis and lung cancer. Of the 300 who became ill, 192 have died to date.

W. R. Grace, the owner of the mine, is the same person who was the subject of the 1995 film, A Civil Action-a movie that alleges that one of Grace's plants in Massachusetts leaked solvents into the water and caused clusters of leukemia.

As soon as the reports were in, the EPA sent investigators in to study the gardener's concerns. They found that five of 16 bags of soil they bought in a local store at random contained asbestos. Three of the five had measurable quantities of the mineral. With one soil, the asbestos fibers became airborne and breathable. This product, which originated at the Grace mine, is labeled Zonolite Chemical Package Vermiculite. Unfortunately, many gardeners use it to create inexpensive potting soil.

The largest problem with this issue is that once asbestos is in the home, it is there forever. It doesn't matter if it is in the garden only.

The EPA says that further research is necessary before it will start banning products. They are testing bags from around the country to determine the contamination level. The results will be available shortly from the EPA hotline at 1-800-368-5888.

In the meantime, the EPA suggests either staying away from vermiculite or, if you must use the mineral, stay outside with it, keep it moist to minimize dust and wash gardening clothes without shaking the dust or dirt off anywhere near the house.

Source: Article based on information from Garden Design Magazine.