Measuring Toxics Use Reduction in the Metal Intensive Industries

This study examined toxics use reduction measurement among metal intensive manufacturers (SIC 34-39) located in Massachusetts. Of the 110 study fms chosen from a stratified random sample, less than half said they documented and measured their toxics use reduction progress. During on-site visits with twenty-eight of these fms, roughly half measured their progress accurately. Toxics use reduction measurement errors were most frequently due to one or a combination of five causes: use of poor normalization factors, inaccurate math calculations, materials accounting mistakes, incorrect chemical balances, and poor production unit definitions. In reconciling these errors, chemical input data was found to be more accurate than byproduct and emission data. Using chemical input data, the study documented over 2.4 million pounds of toxics use reduction at 28 metal-intensive fms. To adjust reductions to the level of business activity, linear regression techniques were used to choose normalization measures which correlated with chemical use. The study found that for 20 chemicals, there was only a 5% difference between normalized and non-normalized measures of toxics use reduction.