Position Paper of the US Composting Council
Environmental Policy and Regulatory Affairs Committee
(August 24, 2001)
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[Submitted to the US Composting Council Board of Directors]

Clopyralid and Composting

Recent incidents have revealed that the composting industry is vulnerable to contamination from a long-lasting herbicide called clopyralid. In several well-documented cases, compost products from clopyralid-containing feedstocks (including grass clippings, animal bedding, and manures) have damaged non-target crops due to the presence of clopyralid.

The U.S. Composting Council (USCC) believes that the existing system governing clopyralid and clopyralid-treated residues does not sufficiently protect compost producers and users. In fact, the existing system has serious flaws that contributed to the aforementioned incidents. Unless the system is changed, the use of clopyralid may prove to be incompatible with composting of yard trimmings and agricultural residues, on any scale and at any facility. The conditions that can lead to clopyralid contamination of compost are beyond the control of compost producers and compost users. We believe that the primary responsibility for correcting the situation lies with the herbicide's manufacturers and suppliers, including Dow AgroSciences. We are encouraged by Dow's reported initial response efforts to date, but believe that additional measures as discussed below must be implemented immediately to prevent further damage to compost users and producers, and to remedy existing damage.

To date the most serious problem appears to be associated with grass clippings treated with the Dow AgroSciences product Confront™. Other products containing clopyralid and other residuals treated with such products are also of concern. In several cases, plant residues treated with these products have carried clopyralid into municipal and institutional composting systems, leading to unacceptably high concentrations of clopyralid in the resulting compost. The levels have been high enough to cause damage to crops grown by some users of the compost. Damage from clopyralid-contaminated compost has been documented in Washington, Pennsylvania and New Zealand (Bezdicek et al, 2001; Fietje, 2001; Houck and Burkhart, 2001; Rynk 2000). Additional cases continued to be reported to USCC members. At this point, we do not know how widespread the problem is. However, we suspect that number of compost producers affected goes beyond the few cases presently documented. The conditions and operations of those documented facilities are not unique. Similarly, the clopyralid-contamination incidents may have resulted from particular circumstances, but those circumstances are not uncommon in the composting industry.

Although this position paper explicitly focuses on clopyralid, we are also concerned about picloram, another herbicide contained in products manufactured by Dow AgroSciences. Picloram is chemically similar to clopyralid, and also has been found in compost at damaging levels. The comments and recommendations made here for clopyralid also apply with respect to herbicide products containing picloram.

SOURCES OF THE PROBLEM

The USCC believes that the current difficulties with clopyralid and composting are due to the following factors:

1. Inappropriate and inadequate labeling of products containing clopyralid with respect to appropriate management of treated residuals.
   
   
2. The inability of even an appropriate label to effectively prevent composting of clopyralid-treated materials and use of clopyralid-contaminated compost.

The label, its flaws and implications

The USCC believes that the information contained on the label for clopyralid products is flawed, and that the label contributes significantly to the current problems. The label for Confront™, as it currently appears on the Dow AgroSciences website, states:

Do not use compost containing grass clippings from turf treated with Confront in the growing season of application.

(Dow AgroSciences, 2001). While not entirely clear, this statement apparently infers that treated residuals can be processed into compost that can be used without negative effect if the composting period extends beyond the season in which the residuals are harvested (i.e., extends for a year or more). This inference is certainly impractical, and its accuracy is doubtful. The label statement also could be read to infer that regardless of the length of the composting period, treated residuals grass clippings can be processed into compost that can be safely used anytime after the growing season in which the grass was treated. However, this statement likewise appears to be inaccurate.

The label recommendation is impractical in that it stipulates a year-long composting period. This is far longer than common practices in the composting industry. Most composting facilities in the U.S. produce compost in a two to six month period. Some facilities produce in as little as 20 to 40 days. Furthermore, significant markets exist for products partially composted for less than a week (e.g., direct land application for grape, berry or rhubarb production). The composting industry cannot drastically modify or curtail its practices to accommodate the presence of a slowly degrading herbicide. A one-year or greater production period for clopyralid-treated residue would place an undue burden on the industry. Such a production schedule would force significant increases in facility size, processing costs, management expense and inventory fees, and would threaten the financial viability of the composting industry.

Even aside from practical considerations, the USCC doubts that even a year's time is enough to adequately reduce the concentration of clopyralid to safe levels. First, "safe" levels for clopyralid are extremely low. Clopyralid concentrations as low as 10 parts per billion (ppb) are damaging to many non-target crops. Some crops are affected at levels less than 1 ppb. Secondly, the compound is relatively slow to decompose. The fate of clopyralid during composting was studied and reported in a paper by Vandervoort et al, 1997. While the research results showed reductions in the concentrations after a year, the data fluctuated greatly. By extending the trend found, it is conceivable that another sample might have shown that clopyralid actually increased in concentration. In any case, the residual levels remaining in the compost at the end of research trial (365 days) was still high enough to damage non-targeted plants. According to this research, even a long term composting scenario would not degrade clopyralid to safe levels. This is corroborated by the situation at a regional composting facility in Spokane, Washington, where over 40,000 cubic yards of finished compost produced from clopyralid-treated grass clippings has been held for 18 months, and still has damaging levels of clopyralid.

Inadequacy of labeling alone to prevent clopyralid contamination of compost

It should be emphasized that the problem did not begin with, nor does it end, with the label. Even if clopyralid applicators are provided with an unambiguous, accurate label, there would still be a long chain of communication that must be maintained among applicators, land owners, harvesters of the plant residuals, haulers and the compost facility operators. How will the applicators know how and where the plant residuals will be handled? How will the land owner know what chemical was applied and how the clippings should be managed? How will the compost facility operator know the history of the residuals delivered in the hauler's truck? As a practical matter, it would be impossible to ensure this essential chain of communication, rendering any improvements to the label ineffectual. A solution to the clopyralid-compost issues must provide for effective and continuous communications among all of the parties involved. If such communication cannot be ensured, the USCC strongly questions the appropriateness of continued uncontrolled use of clopyralid.

IMPLICATIONS FOR ORGANIC WASTE MANAGEMENT

The current situation significantly limits the management options for clopyralid-treated yard trimmings and agricultural residues. The situation likewise significantly limits the potential uses for the compost produced from these feedstocks. Treated residuals would need to be either reused on-site, or disposed in a landfill or incinerator. The consequences of reusing treated residues on site (e.g., the potential for clopyralid accumulation and transport) are unknown. Disposal is not the normal method for handling these residuals, certainly is not a desirable method, and in some locations faces legal barriers. At least 37 states restrict the disposal of yard trimmings in landfills or incinerators. In addition to undermining longer-term environmental goals, disposal often poses higher short-term costs for the user.

ACTIONS RECOMMENDED

Given the situation described above, the U.S. Composting Council urges Dow AgroSciences to immediately implement appropriate corrective measures, as follows:

• Correct the flaws in the label instructions for clopyralid (and picloram). The label should make clear the responsibilities and liabilities of the chemical applicator, the landowner, and the harvester of plant residues regarding the proper disposal or recycling of grass clippings or other clopyralid-treated residues. At a minimum, the label should have a clear and concise statement that treated plant residuals cannot be placed into a compost system.
  
  
• Determine the extent of the problem of clopyralid contamination at composting facilities. This calls for an independent investigation. To date, the problem has been documented at only a few facilities but conceivably the contamination is more widespread. Numerous facilities in many regions handle grass clippings, yard trimmings, and agricultural residues that could be carrying significant amounts of clopyralid (and picloram). A geographically diverse procedure of sampling, bioassays and analytical chemical tests would do much to put the problem into perspective and provide information that would point to appropriate solutions.
  
  
• Thoroughly identify and assess the approved applications for clopyralid, in addition to turf, and the end use of the harvested organic residues from those applications. The investigation should include sampling and testing of residuals and by-products for the presence of clopyralid. For example, wheat straw is used for mushroom cultivation and the by-product from mushroom production is often used for horticulture purposes, with and without additional composting. Grain straw that is used for horse bedding or fodder should also be investigated, as this product is generally land applied in agricultural and horticultural production or composted for general horticultural uses. Washington State University (WSU) recently found clopyralid at levels of 200 ppb in the straw coming from their veterinary medicine facility. Other residues of concern include mint, beets, asparagus, barley and manure from animals that feed on clopyralid treated crops. We are concerned that this herbicide is widely used with little regard for its ultimate fate. Any approved use should be discontinued if there is reason to believe that treated residuals are directed to horticultural or agricultural uses that may damage non-target plants.
  
  
• Until the extent of the problem is determined, and appropriate solutions have been implemented, suspend all efforts to develop and register new clopyralid (and picloram) products or new applications of existing products. The USCC will be asking the U.S. Environmental Protection Agency and appropriate state agencies to consider the use and safety of products made from treated residues as a criteria when reviewing new and existing pesticide products.
  
  
• Where clopyralid-treated residues are affecting the quality and use of compost, discontinue the critical applications of clopyralid, as Dow AgroSciences has done in the Spokane area.

A composting facility that has been inflicted by clopyralid (or picloram) contamination faces serious financial consequences. The incidents at Washington State University and Spokane have been very costly. Through no fault of its own, a facility might lose much or all of its market for compost, be forced to sell product for less than its value and/or have to compensate customers for damage caused by clopyralid-contaminated compost. If the problem continues, herbicide manufacturers, dealers and applicators must be prepared to share the financial burdens resulting from miscommunication and mishandling clopyralid-treated residues. Necessary measures here include the following:

• Compensate compost producers and raw residuals applicators for damages suffered due to clopyralid-contaminated compost. These damages can include:
  • Costs of damaged customer crops
  • Costs for remediating customers' lands ( for example, WSU is supplying activated charcoal for tying up clopyralid residues that would otherwise restrict further horticultural uses)
  • Damages due to a compost facility's inability to meet contractual obligations to supply compost to customers
  • Costs and damages due to loss of organic certification of a compost producer's products, and related lost markets until the producer is eligible to seek re-certification (three years or more). Also, many more composters of organic residuals from both urban and rural sources are currently at risk of losing their organic certification for their products because of the increasingly widespread use of clopyralid.
• Purchase from compost producers, at fair market value, any clopyralid-contaminated compost products.
• Compensate organic growers who used clopyralid-contaminated compost for lost markets and loss of organic certification.

TAKING RESPONSIBILITY

The USCC is concerned that the clopyralid has already begun to erode the compost industry's hard-won reputation as a source of quality products and a method to economically recycle yard trimmings, agricultural residues, and other feedstocks, while rendering them safe from herbicide residues. For most herbicides, that still appears to be the case. However, due to the persistence, low effective concentration, inadequate labeling, and lack of necessary additional controls for clopyralid and picloram, these substances present a significant threat to the composting industry and its customers.

The USCC is encouraged that Dow AgroSciences and the Dow Chemical Company subscribe to the Responsible Care® program of the American Chemistry Council. This program requires dedication to safe handling of chemical products from inception in the research laboratory through ultimate disposal. The USCC is looking to Dow AgroSciences to act on that responsibility now -- to correct the current problems in the system (including but not limited to the flaws with the product labels), and to provide prompt and effective remedies where damage is found. In addition, the USCC is willing and able to assist Dow AgroSciences and other agricultural chemical companies in future evaluations of the fate and acceptability of chemical products within organic recycling systems.

REFERENCES

Bezdicek, David, Mary Fauci, Dan Caldwell, Rick Finch and Jesse Lang. 2001. Persistent Herbicides in Compost. BioCycle. 47(7):25-30

Dow AgroSciences LLC. 2000. Specimen Label for Confront™ (revised 8-07-00). http://dowagro.com/label_system/label_files/us/speclbl/2711.pdf.

Fietje, George. 2001. New Zealand City Confronts Contamination. BioCycle. 47(7):31

Houck, Nadine and Eric P. Burkhart. 2001. Penn State Research Uncovers Clopyralid in Compost. BioCycle. 47(7):32-33

Fietje, George. 2001. New Zealand City Confronts Contamination. BioCycle. 47(7):31

Rynk, Robert. 2000. Dealing with herbicide residues in compost. BioCycle. 41(9):42-47.

Vandervoort, C., M. J. Zabik, B. Branham, and D. W. Lickfeldt. 1997. Fate of selected pesticides applied to turfgrass: effect of composting on residues. Bull. Environ. Contam. Toxicol. 58:38-45.

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