The objective of this program was to determine the feasibility of developing methods for sampling asbestos in the emissions of major asbestos sources. The sources of concern are: (1) ore production including asbestos mining and milling and taconite production, (2) asbestos-cement production, (3) asbestos felt and paper production, and (4) the production of asbestos- containing friction materials. Potential sampling methods must provide samples compatible with the provisional analysis methods using electron microscopy (U.S. EPA Report No. 600/2- 77-178). Visits to the four industries revealed that asbestos emissions can be divided into two classes: stack and fugitive. Inherent differences between stack and fugitive emission environments may necessitate the development of two techniques or at least two modifications of a general technique for sampling. A development program for sampling methods is feasible, given the nature of the emissions and potential sampling environments observed in the industry survey. It is not feasible to undertake a methods development program for strict compatibility with the recommended procedure of the provisional analytical method. Strict compatibility requires the collection of a uniform deposit of proper loading by air filtration on a 0.4 micrometre pore size polycarbonate filter. However, methods development programs are feasible if the sampling method is to be compatible with the* alternative procedures of the provisional method or general electron microscopy. Such procedures require that the collected sample be transferable to an electron microscope grid for counting. The method of sample collection is not precisely specified. Viewed on the basis of components, the essential areas for research toward method development concern collection techniques and removal of non-asbestos material. Practical options for the collection technique component are limited to either electrostatic precipitation or collection by cellulose ester, or polycarbonate filters, despite their known limitations. These techniques may be supplemented by precollection with an impinger to reduce loading. The usefulness as well as the feasibility of a separation during sampling can be assessed only after more thorough data characterizing the industry emissions are obtained and evaluated. The application of inlet and probe technology appears to be a straightforward engineering task.