On Aug. 20, 1999, U.S. Environmental Protection Agency (EPA) issued for public comment its draft cement kiln dust (CKD) rule along with a few thousand pages of support documents. The proposed rule requires that all cement facilities dispose of CKD in lined and covered landfills, and that fugitive dust be controlled where CKD is transported or stored.

It also proposes that CKD used for agricultural purposes be considered hazardous if any of the metal or dioxin constituents exceed proposed thresholds. EPA describes its approach as "creative, affordable, and common sense."

But is it? The purported risks to human health and the environment justifying the rule do not hold up under closer examination. The "hazardous" thresholds are based not on a shred of real data-not a single sample of a plant or animal-but on estimates derived from the infamous "subsistence farmer" scenario.

The EPA model assumes that a farmer lives at the point of maximum exposure to CKD from the facility, the location of which is also determined by a model, and that he and his family are nourished by vegetables grown in their backyard onto which significant amounts of CKD have come to be deposited. All beef and dairy products the family consumes-assumed to be their primary food source-are likewise assumed to be derived from stock grazing on CKD-layered land.

What is the risk to this population? Are there hundreds or even thousands of exposed individuals at risk? Far from it. According to EPA, the current national risk of CKD managed in the United States is an additional 0.0006 cases of cancer each year, according to its models, which tend to significantly overestimate risk for the population of 3.4 million assumed to live within five miles of the plants.

EPA finds this risk to be unacceptable, yet independent studies still have not found a subsistence farmer meeting EPA's criteria living anywhere near a cement plant. "We are about 20 years too late," said one cooperative extension agent. Samples of soil, plants, and animal tissue near cement plants likewise confirm the extent to which EPA models overestimate risk. Other shortcomings in the risk assessment supporting the proposed rule cast doubt on the agency's conclusions that CKD poses a potential danger to human health and the environment.

In an exercise reminiscent of the fox designing the specifications for the chicken coop, EPA expects the economic impacts of managing 3.3 million mt of CKD (1994 figures) to be $44 million at the 68 plants that would be affected by the rule. EPA estimates annual compliance costs will range from less than $100,000 to approximately $3.5 million per plant. The average added cost per plant would be roughly $646,000 per year, or just over $13 per mt of CKD. According to EPA, the average affected plant would face additional costs of slightly less than 2% of sales revenues.

EPA surmises that a "major part" of the compliance cost burden will be shifted to cement consumers (begging the question, "As opposed to who?"). Five to seven kilns, including one entire plant, may close down; and 500 full-time jobs may be lost as a result of this proposed rule in order, according to EPA, to reduce the modeled risk to hypothetical subsistence farmers by 0.0006 cases of cancer nationally per year-essentially, to eliminate all exposure to CKD. Is this creative, affordable, and common sense? Not really.

Even assuming the hypothetical subsistence farmer exists, CKD management issues are dominated by a relatively few facilities. Only 15 wet-process facilities (out of 110 portland cement facilities nationwide) generate 90% of the nation's CKD. Regulating CKD as a hazardous waste at the federal level is therefore using the proverbial sledgehammer to kill a fly, albeit a bothersome one if it happens to be in your immediate vicinity, which indicates the need for local response.

Indeed, the American Portland Cement Alliance has proposed to EPA that CKD be regulated at the state level since states are better equipped to deal with isolated instances of CKD management. This makes sense, as local conditions and control measures will vary quite a bit from state to state.

Making generic federal rules that effectively control emissions from 15 key facilities already operating under state permits is neither an effective nor efficient means of controlling a localized CKD issue, particularly with the number of wet-process kilns declining over time. Managing CKD at the state level also would avoid attaching the inevitable stigma of hazardous waste to a beneficial use that has been practiced for decades. There also is the question of how the risks of CKD applied to land compare with other land-treated materials. In January 1994, EPA and the American Forest and Paper Association negotiated a Memorandum of Understanding (MOU) regarding the implementation of land application agreements among member companies and EPA. This MOU included standards for management practices, monitoring, and reporting requirements, and concentration limits for land-applied sludge.

A similar kind of arrangement exists between EPA and the many municipalities that must apply metal-, pathogen-, and bacteria-laden wastewater treatment sludge for agricultural purposes without adverse impact.

These precedents would seem to be appropriate starting points for similar state agreements on how to manage CKD appropriately, an issue of much smaller scale and environmental significance. Indeed, EPA states in the proposed rule that it believes "there may be no need to finalize a federal program if states with cement facilities that dispose CKD adopt appropriate programs and standards for managing CKD."

In addition to the permitted waste-burning facilities, these rules will also apply to facilities not burning hazardous waste. An attempt by the Non-Hazwaste Burner CKD Coalition to get CKD from non-hazwaste burning facilities off the list was not successful. In fact, EPA agreed that "the total concentrations of metals in CKD were not significantly different whether the dust was generated in kilns that burn or do not burn hazardous waste. Likewise, leach test results show that no significant distinction can be made." The new management standards in the proposed rule also replace the exemption of CKD from hazardous waste regulation under the Bevill exemption.

The 90-day deadline for public and industry comments to EPA ended on Feb. 17, 2000. With no set date for a final decision by EPA, the wait for the definitive ruling on CKD begins.