Abstract: A stemming agent is provided comprising: A) a neutralized acrylic acid polymer; B) a neutralized mixture of sodium silicate and a silicon oxide-containing material such as sand, clay, stones, volcanic ash, or the like; or C) a mixture of materials A) and B). The stemming agents produced are low cost, easily made, and preferably are free of nitrate salts. Accordingly, the use of these preferred stemming agents eliminates the contamination of ground water by nitrate salts. The stemming agents of the invention may be used in either bulk-delivered or packaged applications.