Reported expenditures for environmental protection are often cited as an assessment of the burden of current regulatory efforts. However, the potential for both incidental savings and uncounted costs means that the actual burden could be either higher or lower than these reported values. Using a production cost model that considers the possible interaction between environmental and non-environmental expenditures, we directly estimate the dollar-for-dollar incidental savings/uncounted costs arising from a one-dollar increase in reported environmental expenditures. Although recent literature supports the idea that reported expenditures probably understate the actual burden, we find no such evidence in the manufacturing sector based on a large panel of plant-level data. In one industry, we find statistically significant overstatement. In three others, we find no significant deviation in either direction. We conclude that, although cost estimates are not overstated on average, variation and uncertainty exist at the industry level, with some plants experiencing savings and others possibly facing uncounted burdens.