The findings indicate the importance of detecting the presence of the following explosive residues on swabs from crime scenes: ammonium, nitrite, perchlorate, thiocyanate, chlorate, and cyanate ions. These should be considered important markers for the presence of inorganic explosive residue due to their low levels of normal occurrence in the environment. More common explosive residue ions such as nitrate, chloride, and sulfate were detected in a high proportion of samples, proving their prevalence in the environment. Sodium, potassium, calcium, and magnesium were also found to be common ions in the public environment. Constituents of high explosives were found to be extremely rare in most public access areas. The objects swabbed in the 28 cities ranged from park benches and telephones to sign posts and mailboxes. A description of materials and methods addresses the chemicals and standards used. Sampling was performed with custom prepared kits. Each kit contained a vial with a blank cotton ball (rinsed with deionized water and organic solvent), a pair of gloves, a template, and a pair of disposable tweezers. The description of the analysis of the sample addresses capillary zone electrophoresis and electron capture detection. 2 figures, 2 tables, and 9 references