Some gardening products contain levels of asbestos, but the risk to consumers is very low, EPA said Tuesday.
Vermiculite is a naturally occurring granular substance mined for uses in horticultural products and insulation materials.
For lawn and garden use, it is often found in potting soil.
The agency study of 38 vermiculite products from around the country found five that could expose people to asbestos and 17 others with trace amounts.
All five products with higher asbestos levels were straight vermiculite, which is often mixed with soil by consumers.
"EPA is making this information available as part of our effort to expand the public''s right to know and protect public health and the environment," said Susan Wayland, acting assistant administrator for the Office of Prevention, Pesticides, and Toxic Substances. "These levels were very low and do not pose significant health risks. However, we do feel it is important for consumers to be armed with this information when making their decisions."
EPA''s report raises questions about the potential risk to workers who may use vermiculite products on a regular basis and face significantly greater exposure.
OSHA and the Mine Safety and Health Administration (MSHA) said they were investigating the asbestos exposure of people who regularly work with vermiculite.
Asbestos is a natural, minor contaminant of the ore from vermiculite and can pose a risk if fibers become airborne and are inhaled into the lungs.
Breathing high levels of these fibers, which are so small they float in the air unseen, can lead to an increased risk of lung cancer, mesothelioma and asbestosis.
EPA recommended that consumers use premixed potting soils, which produce less dust. People mixing their own vermiculite with soil should work outdoors or in a well-ventilated area and keep the vermiculite damp to avoid dust.
The agency is also developing a set of standard scientific protocols for sampling in-place vermiculite insulation in the attics and walls of people''s homes to help assess the potential health risks.
To obtain a copy of the study or to find more information about asbestos, visit EPA''s Web site at www.epa.gov.
by Virginia Sutcliffe