Prevalence of asbestos in composted waste from 26 communities in the United States

Composting of yard waste, sewage sludge and municipal solid waste (MSW) for subsequent application to soils in agricultural, horticultural and recreational areas is being promoted nationwide. Since asbestos is a common contaminant in sewage sludge, an analytical survey was conducted for the presence of asbestos in composts collected from 26 communities nationwide resulting from sludge as well as yard waste and municipal solid waste. Asbestos was detected in 12 of the 26 composts or 46%. Asbestos was most consistently present in compost resulting from source material containing MSW and to a lesser extent sewage sludge rather than yard waste. The possible origins of asbestos in the compost source material, the mechanisms by which humans may be exposed, and the health significance are discussed.