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Working with excavators clearance systems to proactively inform of environmental and health hazards

The excavation limits of a new water main are marked on the street. Consistent with state regulation, the excavator calls in the excavation limits to the One-Call System. Soon the street is marked with utility locations. Surprisingly, the excavator receives a fax describing that the excavation site as occurring in a zone of environmental contamination. The responsible party who faxed the notice of contamination is pleased to have averted a hazardous substance release and to have protected the excavators and the public from harm. The excavator, however, is not pleased; their fixed bid did not anticipate the cost of handling contamination and work delays.  Can we improve the use of One-Call Systems, and have these two stakeholders be friends? This article describes the appeal and the challenge of using One-Call Systems to notify those who need to know of the existence and location of engineering controls (ECs) and institutional controls (ICs). The article is divided into seven sections:

  • Background on ECs and ICs
  • The Need to Protect ECs and ICs from Excavation
  • Why Can’t Excavators Call Before They Dig?
  • Benefits of Using One-Call Systems to Protect ECs and ICs
  • Experience with Using One-Call Centers – the One-Call Pilots
  • Excavation Contractor Concerns and Issues
  • Next Steps

Background on ECs and ICs.

ECs and ICs exist because of risk-based cleanups.  Underground environmental pollution is older than the industrialization of civilization, and it used to be largely ignored.  Within the United States there are 500,000 to 750,000 sites with underground contamination.  Now that cities need to reduce sprawl, and clean up old industrial land for redevelopment, underground pollution is increasingly problematic to ignore. Fortunately, with an information-based economy, the Internet, and online GIS-enabled databases, information technology can help protect human health and the environment from underground pollution.  It has become a matter of getting the right information to the right people at the right time. Why is information on underground pollution needed? Why not just clean it all up? Information on underground pollution is needed because such information has become a key component of containing the risk in risk-based cleanups. Risk-based cleanups anticipate some future industrial or commercial land use scenario. Based on this scenario – which the community agrees upon – ECs and ICs contain contamination and therefore reduce risk enough to levels that are safe for the community’s new land use scenario. Other factors beside the recent flurry of Brownfields and Superfund cleanups (e.g., more infill development, underground utilities, and transportation construction) increase the need to protect future construction from breaching the containment that ECs and ICs provide, defeating the remedy, harming people, and increasing construction contractors’ liability exposure.

The Need to Protect ECs and ICs from Excavation.

While most contamination originates from a discrete source, it can spread through the movement of ground water into large areas that underlie other property and public rights-of-way. Whether contamination would expose excavators to harm depends upon the location and depth of the excavation and on whether information gets to the right people at the right time (such information would consist of a series of EC and IC warnings that are “layered” so that the first warning goes to the engineers that design the excavation). Contractors are at the front line, and unknowingly can expose their employees, as well as the public, to buried hazardous substances if they damage an EC or inadvertently mismanage the disposal of soil or dewatering fluids.

Why Can’t Excavators Call Before They Dig?

Nationwide, approximately 50 million excavations each year are cleared by regional notification centers. Buried infrastructure owners are required to confidentially store their underground utility locations in a database maintained by the notification center. Before excavating, an excavator marks the location of an excavation with paint on the street, and then calls the notification center with the location and timing of the excavation. The clearance center then notifies the utility owners who have the responsibility to inform the excavator about utilities they may encounter. These clearance centers are funded through fees paid by the owners of underground utilities.

States developed One-Call Centers pursuant to legislation drafted to prevent inadvertent damage to buried infrastructure — not to ECs and ICs.  Yet, ECs and ICs share many common elements with underground infrastructure; they are generally undetectable at the surface, typically have an owner, and cause tremendous economic, safety and environmental impact if breached. Because of these common elements, there has been a growing interest in using the already existing One-Call systems to provide one layer – the last layer of defense to prevent the breach of ECs and ICs.  Should protocols be crafted to recognize the pervasiveness of risk-based cleanups and prevent inadvertent damage to ECs and ICs by including them in One-Call Systems?

Benefits of Using One-Call Centers for ECs and ICs

  • High Compliance of Users.  The statutory obligation coupled with a high awareness of the system, makes a most excavators use the One-Call Centers. It would be difficult to replicate the One-Call system for management of ICs.
  • Large Service Area.  With approximately 60 One-Call Centers nationwide, using this large existing infrastructure offers a more efficient data transfer channel than attempting to create something new to serve the 45,000 local governments in the nation.
  • Target Audience. The One-Call Centers are targeted on the exact activities that would likely breach ECs and ICs.
  • Understood Costs.  Because the One-Call Centers have an established fee basis, the costs of utilization are understood and predicable.

Experience with Using One-Call Centers – the One-Call Pilots.

There have been several attempts to transmit ICs and ECs through One-Call Centers.

  • Oregon.  The City of Portland entered 10 sites into their One-Call system. The City then faxed summary site notifications to the excavators.  Unfortunately, this successful project was halted due to lack of funding.
  • Wisconsin.  The Wisconsin Department of Natural Resources (DNR) joined the “Diggers Hotline.” In the project, they successfully provided site boundary information (latitude & longitude plus a radius buffer).  DNR performed hotline member obligations including receiving and screening the location of tickets that were received by fax. The excavator was contacted if a conflict existed. DNR screened tickets only to prevent water well installations. DNR ceased because they could not discern the depth of the excavation, and the manual review of the many tickets they received was burdensome and costly.
  • Pennsylvania.   This pilot combines the efforts of EPA, the Pennsylvania Department of Environmental Protection (PA DEP), and Pennsylvania One-Call System, Inc. (POCS). This pilot is evaluating the feasibility and impact of regulatory or legislative changes that would expand the Pennsylvania One-Call legislation to expressly cover subsurface contamination, or otherwise require residually contaminated sites to join POCS.  Such amendments would mark the first step, nationwide; to formally require owners/operators of residually contaminated sites to join the One-Call system.
  • California.  Terradex, Inc. joined as a locator on behalf of the Owner/Operator of the ECs and ICs. Terradex performs geo-spatial comparison of excavation, and reviews excavation attributes to determine if a conflict exists. Terradex contacts the excavator for more information, typically excavation depth, if warranted. If a conflict exists, Terradex alerts the excavator, the owner/operator and the oversight agency. Terradex became a member of USA South and USA North, and provides positive responses to all tickets received consistent with guidelines. Through an EPA pilot, and more recently for commercial clients, Terradex has screened thousands of excavation notices.

Excavation Contractor Concerns & Issues.

Contractors have raised various concerns about the use of the One-Call System for transmitting EC and IC location information.

  • Inadequate Notice Period. The convention is to provide two business days notice before excavation proceeds. Receiving the first notice of and existing environmental hazard less than two days before work is disruptive and expensive.  By this time, all permits have been issued, and fees negotiated for the project. Requirements to manage environmental contamination should have been developed by the engineer or owner.
  • Regulatory Oversight Not Welcome.  The excavator wishes to proceed with work expeditiously, and the potential for environmental regulatory involvement just prior to digging is not perceived constructively.
  • Responsibility of Others.  By only providing notice to the excavation contractor, sole reliance on the One-Call System shifts the burden of managing environmental contamination to the excavator.  Excavation contractors argue that the permit writers, developers, engineers, and drafters should have notice of the location of the ECs and ICs.
  • EC and IC Location Can Be Vague.  Different than the fixed location of a pipe, the occurrence of environmental hazards can be uncertain. Suspected contamination may or may not be encountered in a given excavation.
  • Risk of Over Notification. The number of excavation tickets in conjunction with the number of contaminated sites could generate too much notice and trivialize the process, as in the Wisconsin pilot.
  • ECs and ICs are Not the Intent of the One-Call System.  Excavators have agreed to participate in order to prevent damage to underground infrastructure.  Introduction of environmental hazards constitutes an expansion of the One-Call System to a different type of damage and a different type of infrastructure.

Next Steps.

A principal premise for the excavation and contracting industry is providing for the safety of their work force. When information about ECs and ICs can be delivered in a constructive manner into the project, construction can be safer. As an approach is developed, several premises should guide its design:

  • Layered Approach Where One-Call Notification is The Last Step.  ICs must be revealed earlier in the development process.  ICs should be discovered within the design phase, and be considered in the bid process. Therefore, the owner or engineer of the project would be better informed than the excavator. Contractors have invited a national one-stop registry for ICs and ECs.
  • ICs Should Be Available to the Design Community.  The ICs should be available to engineers in the planning stage of a project. If the ICs were planned for, then receiving notice of ICs would not be burdensome to the excavator. Contractors are encouraging the creation of a geospatial registry of ECs and ICs that could be accessed by designers and contractors early in the design process and long before the clearance call is made to the One-Call System.
  • ICs Should Be Available In Building Permit Process.  The building permit process provides an earlier stage to check for the occurrence of underground environmental hazards.
  • ICs Should Be Useful and Relevant to the Excavator.  Where possible, information conveyed to the excavator should transmit what media is contaminated (soil, groundwater, vapor), the depth of contamination, and available contacts.

In the long-run, statutory changes will be needed to legitimize the use of One-Call Systems for transmitting the location of ECs and ICs.  First, the storage of the boundaries of ICs should be permitted to be placed within One-Call System databases; now the systems are typically limited to the boundaries of underground physical infrastructure.  Similarly, the party responsible for the residual contamination (or their designee) should be allowed to be a member of the One-Call System. It is expected that the liability protections accorded to excavators and members would be extended as possible to encompass the management of underground environmental hazards.Other next steps that should be considered include the following:

  • Develop a Working Paper with the Common Ground Alliance. The Common Ground Alliance (CGA) is a national organization representing the stakeholders of the One Call Systems. With the help of CGA, and through the creation of a Working Paper, improvements to the One-Call Systems could be considered, as well as ways to promote IC and EC registries within the design and excavation community.
  • Encourage Pilots. Support One-Call Systems that choose to participate in pilots transmitting the ICs. These pilots would constitute research and development activity within CGA. Allow some discretion of One-Call Centers that chose to experiment with ICs. To date, it appears that the chance for work interruption is relatively remote, and that a third party – possibly a commercial venture – is valuable to screen the continuous flow of excavation tickets.
  • Critique on Model Designs for Notices of ICs and ECs within the One Call System. This would help assure that the information provided to design professionals, owners, and ultimately an excavator is useful in the construction process..


In the future we revisit our excavator as a result of successful collaboration to build a mechanism to transmit information about ICs and ECs to the design and construction community.  Through a geospatial registry of ICs and ECs, the project engineer has realized that the route of the water main passes through a zone of contamination, and the water main’s design must protect existing ECs and accommodate limitations posed by an IC. This time around, the excavator’s bid planned for the impact that the ICs and ECs have on the project. There were no surprises when One-Call System faxed notice of the ICs and ECs to the excavator.  The responsible party used the notice to dispatch field staff to provide assistance to the excavator.

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