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Closed Connections

June 28, 2013
The UVM industry creates a best management practice for adoption of a closed chain of custody for herbicide use.

The utility vegetation management industry uses herbicides extensively to maintain vegetation on electrical utility rights-of-way (ROW). Herbicide use helps to keep ROW free from tall-growing tree species that might otherwise pose a risk to power system reliability. Maintaining ROW vegetation also helps to ensure access for inspections, maintenance and emergency repairs.

Traditionally, herbicides used in utility vegetation management (UVM) have been supplied in concentrated forms in non-returnable containers. This requires mixing and loading open containers of concentrate on job sites. Advances in chemistry and application methods have significantly reduced the volume of herbicide solutions applied. Low-volume application techniques and herbicide formulations have made it practical to adopt ready-to-use and diluted concentrate formulations in closed-delivery systems — a practice that further protects the applicator and the environment. Not only is the applicator’s safety enhanced, but utilities can save time and money by using closed-delivery systems.

Closed systems enable the secure transfer of herbicides from drum to backpack.

However, until recently, only limited attention has been focused on the logistics of shipping, storing, mixing and handling of herbicides, as well as managing the waste stream, including rinsates and empty containers. The Utility Arborists Association (UAA) saw both a need and an opportunity to demonstrate leadership by developing a best management practice (BMP) focused on a state-of-the-art strategy for managing the chain of custody for herbicide use — from producer to distributor and custom blender, through applicator to application — on a ROW. The BMP also addresses the handling of empty supply containers.

The UAA believes this BMP is a demonstration of proactive industry self-regulation and a clear demonstration of the UAA’s commitment to environmental stewardship.

Closed Chain of Custody

The closed chain of custody concept includes herbicide formulation, shipping, distribution, storage, mixing and application. It also includes the return of empty containers for refilling and reuse.

There are four important elements to the closed chain of custody:

  • Container cycle. Supply containers are returned, refilled and reused.
  • Integrity cycle. Closed connections are made at the transfer points between supply containers, mix tanks and application equipment.
  • Documentation cycle. A container tracking system establishes an auditable record documenting the movement of herbicides and containers.
  • Herbicide cycle. Herbicide formulations are delivered as custom blends that contain active ingredient and any necessary adjuvants.

Returnable, Reusable Supply Containers

The BMP promotes the use of supply containers that are returnable, reusable and, ultimately, recyclable. There are inherent advantages associated with this concept. The supply containers are filled by custom blenders and are the vessels in which custom blends are provided to the applicator.

Reusable closed-supply containers are easy to refill.

These robust supply containers reduce the likelihood of leakage from container damage. Also reduced is the risk of regulatory noncompliance, such as the application of off-label rates or improper disposal of rinsates and empty containers.

Closed Connections

The BMP is intended to promote the use of closed interlock valve connections at each transfer point, where herbicide is being moved from one container to another container or tank, including application equipment supply. There are advantages with the use of returnable, reusable closed-supply containers.

Maintaining closed connections at transfer points throughout transportation, filling and application reduce personnel exposure to concentrated herbicide products. Closed connections at transfer points also may reduce the likelihood of leaks and spills during handling, mixing and loading.

Tracking and Record Keeping

The BMP provides for an auditable record documenting the movement of herbicides and containers through the chain of custody, from producer to distributor, to custom blender, to utility, to applicator and back to custom blender (with the return of empty containers).

Custom Blends

Additionally, the BMP strongly promotes the use of custom blends, which reduce the potential for measuring errors during loading and mixing. This comes from the combined strategies of using blends that include all required ingredients and the use of closed connections.

There is a closed connection between supply container and the applicator’s equipment.

The use of all-inclusive custom blends of diluted concentrates reduces the likelihood of errors in measuring the proper quantity and during mixing operations. It also ensures the integrity of the intended formulations, including active ingredients, diluents and adjuvants by reducing the likelihood of unauthorized changes in rates or substitutions. When diluted concentrates are supplied in volumes that match spray tank requirements, the need for measuring can be eliminated, just as they are in the case of ready-to-apply formulations.

Utilities and applicators that focus on a few basic core mixes for their specific programs and projects are more likely to realize the full benefits of returnable, reusable closed-supply containers. The intent of the BMP is to encourage increased standardization within individual operations. The BMP also acknowledges the need for an adaptive UVM strategy that anticipates the need to make changes in application-ready mixtures at the time of application as a result of changing weather or site conditions.

Benefits of the BMP

There are sound operational reasons for adoption of the practices described in the new UAA BMP. Maintaining closed connections at transfer points throughout the transportation, filling and application system, as herbicides move from supply containers to mix tanks and application equipment, reduces the handler’s and applicator’s exposure to herbicides. The use of custom blends of diluted concentrates and ready-to-apply formulations reduces potential exposure to concentrated herbicide products.

Containers are marked for measuring quantities of custom blends.

The use of returnable, reusable supply containers reduces the volume of the waste stream associated with UVM operations. Firstly, the number of one-way containers that must be disposed of in a landfill is reduced. Secondly, there is a reduction in the volume of rinsate generated by a spray crew because returnable, reusable supply containers eliminate the need for triple rinsing empty containers before refilling. The volume of rinsate generated by the use of conventional, open one-way disposable containers is significant, though it can be reused as part of the diluent in the next batch of mix being prepared.

Crew personnel that had used custom blends in reusable closed containers were reluctant to return to the use of open one-way containers, and applicators that had incorporated the practices in their operations brought them to work on other utility systems.

The Financial Assessment

While the operational benefits of the BMP have become clear to practitioners, financial analysis has confirmed the closed chain of custody BMP is cost-effective. The financial analysis of the economic implications of implementing the new closed chain of custody BMP was broken down into four previously described elements:

  • The use of returnable, reusable supply containers
  • The use of a closed system
  • The use of an improved means of tracking supply
  • containers
  • The use of custom blends versus concentrates.

The financial analysis was conducted in such a way that the cost of implementation and financial justification for each element could be considered a separate initiative.

The economics for each initiative were examined and calculated, as appropriate, for the aggregate of all stakeholders (utilities, distributors, custom blenders and applicators) into a supply-chain-wide five-year net present value. The key reference metric is the cost differential of a mixed ready-to-apply gallon in a spray tank. This was a calculation made by comparing the traditional use of packaged goods in open one-way containers with the corresponding element in the closed chain of custody BMP.

The five-year net present value, given a yearly cost of capital of 9% (the cost of capital is an average for 2009 taken from various asset owners, distributors and custom blenders), is presented individually and in composite in the table for each of the four aspects of the closed chain of custody BMP.

The adoption of returnable, reusable supply containers is net positive across all four application types. This is because of the two main contributing factors: the avoided cost of proper disposal of one-way containers and the incremental improvement in crew productivity related to the efficiency of transferring and mixing herbicides.

The adoption of closed connections comes at a premium. There is an immediate benefit from more accurate herbicide mixing, thereby reducing waste as well as spillage-induced liability, but it is countered by the initial capital cost to refit herbicide application equipment. However, when combined with returnable, reusable closed-supply containers, the benefits are net positive.

Improvements in tracking are economically positive, primarily because of better inventory management. There also are savings in the purchase cost of formulations such as custom blends, except in the case of low-volume foliar applications. When all elements of the closed chain of custody BMP are considered together, the results are net positive, as reported in the right-hand column of the table.


Financial analysis conducted as part of this project demonstrates this new BMP can be adopted at no additional cost to the UVM industry. To be clear, the analysis was conducted at the UVM industry level, which considered the net cost to all parties in the supply chain. It is likely that, at least in the short term, there will be inequity in the costs and benefits among various stakeholders in the process, as some bear costs in excess of any direct benefit they might receive. However, in an efficient marketplace, any initial unintended cross-subsidization would be reconciled, as costs and benefits true up.

Technical specifications for the BMP are available from the UAA, as is a copy of the project report that describes the investigation and process used to develop the BMP. The technical specifications are intended to be easily adopted by utilities, by referencing it in UVM procurement specifications. A field handbook for crews is available from the International Society of Arboriculture.

The UAA analysis demonstrated that adoption of the BMP can reduce the risks of mixing errors and spills, as well as applicator exposure. Adopting the BMP is a demonstration of good environmental stewardship. The BMP also provides utility asset owners with a useful resource that can be incorporated in the procurement of vegetation maintenance services that involve the application of herbicides.

John W. Goodfellow ([email protected]) is a principal consultant for BioCompliance Consulting Inc. and a vegetation management researcher with more than 30 years of experience in the electric utility industry. He has held positions of responsibility for vegetation management, engineering and field services at three large investor-owned electric and gas utilities. He also has managed T&D services for a major contracting organization. He has bachelor’s degrees in forestry and natural resources management from Syracuse University and the SUNY College of Environmental Science and Forestry.

Arkan Kayihan ( is an internal management consultant at the University of Washington Medical Center. He holds chemical engineering degrees from the University of Washington (BS) and Purdue University (MS), as well as an MBA from the University of Washington.

Sidebar: Integrating Sustainability into a Herbicide Program

By Michael Neal, Arizona Public Service

In 2006, Arizona Public Service (APS) began reclearing its transmission rights-of-way (ROW), but the utility did not have a formal herbicide program in place. A more formal approach would make sense in the desert southwest, as there are significant challenges to applying herbicides across seven different climate zones, within varying biotic communities, often combined with difficult terrain and limited accessibility to power lines.

APS decided to work with John Goodfellow, a principal consultant for BioCompliance Consulting Inc. and a vegetation management researcher, who authored “Best Management Practices for a Closed Chain of Custody for Herbicide Use in the Utility Vegetation Management Industry.” APS was committed to achieve environmental stewardship while properly applying herbicides under often difficult situations.

After reviewing available herbicides, APS selected the use of ThinVert over water, a concept presented to APS by Rick Johnstone of IVM Partners Inc. The utility’s investigations showed that with ThinVert, evaporation would not be an issue. At the same time, the chemical would have better plant adhesion, improved leaf penetration and greater drift resistance. ThinVert also had extended temperature thresholds and increased rain fastness. Because an applicator will only use 40 gal (151 l) of ThinVert in a full day, there is also no need for a separate water source, resulting in lighter loads.

APS hired herbicide applicator Southwest Ground Control (SWGC), who was willing to embrace new methods of handling and spreading herbicides. In fact, APS recognized SWGC as vendor of the year for its pioneering work with this program.

APS agreed to a scope of work within the contract for services signed by SWGC to ensure best management practices. The fixed-lump-sum bid calls for an initial application to obtain a 90% control of undesirable species. The second application will provide touch-up the following year to obtain 100% control of undesirable vegetation.

APS requires 100% herbicide coverage of the stems that are 3 ft (1 m) tall or greater and within the ROW that can grow within spark-over or contact with the conductors. For all other target vegetation less than 3 ft in height, a minimum herbicide coverage rate of 90% is required. At the time of application, the contractor also will be required to treat all non-native invasive plants of Arizona in the ROW corridor.

The most critical treatment area within the ROW is the wire zone. The contractor should be well organized and use good communication to ensure complete coverage without spraying areas multiple times and over applying.

The contractor will follow up with a touch-up application the following year to control the remaining undesirable vegetation and non-native invasive plants of Arizona.

The contractor must use brand-name herbicide products manufactured in the United States. The contractor is to provide its mix rates and calibrated volume rates per acre for broadcast treatments. Thinvert shall be used for all foliar applications.

The use of mechanized equipment should be limited in these areas to only that which is absolutely necessary for the work to proceed. All herbicide applications within these buffer areas will be through the use of appropriate wetland or aquatic herbicide mixes, which are federally labeled for such use. A wetland/aquatic labeled mix is the only approved method of herbicide application within the stream-side management zone. These herbicides are limited to Garlon Habitat or Accord. APS will supply the contractor with all known wetland areas.

As part of APS’s sustainability program, the contractor will be required to use returnable, refillable containers along with a closed-loop transfer system.

Sidebar: Going to a Closed Chain of Custody System

By Larry Abernathy, Davey Tree Surgery Co.

The Utility Arborist Association’s recent study “Best Management Practices for a Closed Chain of Custody for Herbicide Use in the Utility Vegetation Management Industry” makes a pretty clear business case for utility adoption of a closed container management system for herbicides.

Davey Tree is active in the Utility Arborist Association and always looks to follow best management practices to improve business processes and enhance environmental stewardship. Davey Tree crews routinely perform tree removals to meet clearance requirements according to the state of California and also to meet NERC/FERC reliability standards. Crews typically follow up with a cut-stump herbicide treatment, especially when working with hardwood species to reduce the need to re-treat.

Davey Tree’s California crews had followed industry norms using disposable one-way herbicide containers to receive herbicide concentrates for their right-of-way applications. Workers opened and poured concentrates into spray equipment tanks to prepare spray solutions, and they ultimately had to dispose of empty containers according to label directions.

 The company recognized that it was labor-intensive work, and there was also an opportunity for error in terms of inventory management as well as when mixing herbicides on site. This can affect control rates, and it also unnecessarily exposes workers to herbicides.

Davey Tree brought in Scott Johnson, a vegetation management specialist with Wilbur-Ellis Co., to develop a closed container management system to eliminate mixing of chemicals in the field. Davey teams now receive premixed custom herbicide blends with exact concentrations that ensure higher rates of treatment control.

Representatives from IVM Partners, Wilbur-Ellis Co. and Eco-Pak, LLC worked to deliver the Dow AgroSciences Continuum Prescription Control & Container Management System using returnable, refillable containers. This arrangement also provides Davey with the custom blend it uses for all its cut-stump treatments across California, as well as a custom bare ground mix used by its applicators in Southern California for treating utility poles. Working in concert with the Continuum system, ProVM assures applicators that all state compliance is met, which is especially important in California where mandatory pesticide use reporting is required for each individual application.

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