Bis(chloromethyl)ether (542881) (BCME) formation from formaldehyde and chlorides was investigated, and BCME contamination selected industrial environments was evaluated. BCME formation was tested in gas phase and in polar (methylene-chloride) and nonpolar (carbon- tetrachloride) condensed phases. BCME formation was greatest in the polar medium. Reaction mechanisms were postulated, rate equations were integrated, and trapping techniques and analytical procedures were evaluated. On site surveys at two textile finishing facilities (SIC-2261), one fertilizer factory, (SIC-2819), two dye manufacturing facilities (SIC-2865), two foundries (SIC-3361), and one hospital procedure resin production laboratory (SIC-8071) revealed no BCME contamination. The highest amounts of formaldehyde were found in foundry and dye manufacturing facilities; the highest total chloride was found in a fertilizer factory. The authors recommend that the coexistence of formaldehyde and chlorides be avoided to minimize the formation of BCME. For industrial processes utilizing both of these components, substitutes for either of the two must be found.