The United States is heavily dependent on transmission pipelines to distribute energy because they are the safest mode available for transporting energy fuels. Virtually all natural gas, which accounts for about 28 percent of energy consumed annually, and two-thirds of petroleum products are transported by transmission pipelines, which make up 20 percent of the 1.8 million total miles of pipelines in the United States. Energy demand has increased by about 35 percent in the last decade, and recent estimates indicate that the demand for energy fuels may increase by another 36 percent between 2002 and 2010.
The nation’s projected demand for energy, particularly in new and fast-growing metropolitan areas, may require many additional miles of transmission pipelines. Increasing urbanization, which is accompanying the increasing demand, is resulting in more people living and working closer to pipelines. In many cases, development near pipelines is occurring in formerly rural, unincorporated areas long after pipelines have been constructed but before local agencies develop land use regulations that take into account the risks of allowing such development to occur. Given these projections and the fact that pipeline incidents occur almost daily in the United States, regulatory agencies at the national level view pipeline safety as an issue that needs to be addressed.
In recent years major pipeline incidents have occurred, and public opposition to the construction of new pipeline rights-of-way has increased. These events have focused more attention on the need to assess carefully and rationally the actual risks associated with living and working in proximity to transmission pipelines and to consider land use controls near pipelines that will allow people and pipelines to coexist in a manner that does not pose undue risk to each other. In December 2002, Congress
enacted the Pipeline Safety Improvement Act of 2002, which requires the Secretary of Transportation, in conjunction with the Federal Energy Regulatory Commission and in consultation with other relevant agencies, to conduct a study of population encroachment on rights-of-way. The Office of Pipeline Safety (OPS) in the U.S. Department of Transportation (USDOT) requested the Transportation Research Board (TRB) to assist in meeting this legislative mandate. Specifically, TRB was asked to convene a committee to consider the feasibility of developing risk-informed guidance that could be used in making land use-related decisions as one means of minimizing or mitigating hazards and risks to the public, pipeline workers, and the environment near existing and future hazardous liquids and natural gas transmission pipelines. In addition, the committee was asked to consider environmental resource conservation issues (e.g., preservation of trees and habitat) in pipeline rights-of-way.
Transportation of energy fuels via transmission pipelines is safer than transportation via other modes, but a significant failure can result in loss of life, personal injury, property damage, and environmental damage. In the last 3 years, hazardous liquids pipeline incidents have resulted in an average of 2 deaths, 11 injuries, and $97 million in property damage each year; natural gas transmission pipeline incidents have resulted in an annual average of 6 deaths, 10 injuries, and $20 million in property damage. From 2000 through 2002, the annual average number of gross barrels of hazardous liquids lost was 100,000, a decrease from the annual average of 270,000 gross barrels lost in the 1986 to 1989 time period. There are many causes and contributors to pipeline failures, including construction errors, material defects, internal and external corrosion, operational errors, malfunctions of control systems or relief equipment, and outside force damage (e.g., by third parties during excavation). Excavation and construction-related damage to pipelines remain the leading causes of pipeline failure. Such failures in 2003 were estimated by USDOT to contribute 22 percent of hazardous liquids and 24 percent of natural gas transmission pipeline incidents. With the growth in popula-
tion, urbanization, and land development activity near transmission pipelines and the addition of new facilities, the likelihood of pipeline damage due to human activity and the exposure of people and property to pipeline failures may increase.
LAND USE MEASURES
Awareness is growing among federal agencies and the pipeline industry that risk-based approaches to managing pipeline safety should be considered for the following reasons:
The exposure to hazards associated with proximity to transmission pipelines carrying various commodities involves significant uncertainties.
More people are living and working closer to transmission pipelines.
Some new transmission pipelines will be constructed in densely populated areas.
Recently, OPS implemented the Integrity Management Program, a regulatory approach that requires pipeline operators to comprehensively assess, identify, and address the safety of pipeline segments that are located in areas where the consequences of a pipeline failure could be significant. However, this effort does not incorporate land use measures (e.g., comprehensive plans, zoning, and setbacks) that could be employed to manage the risks because such measures are primarily the responsibility of state and local governments.
The terms “land use” and “land use practices” are normally used to describe policies and practices of local governments that regulate the planning, development, and use of land. The committee expanded this definition to include a broader range of actions taken by all stakeholders— pipeline operators, regulators, contractors, private property owners, and the public—affecting the immediate vicinity of pipelines.
Under such a definition, the most common land use measures employed to preserve the integrity of pipelines involve actions taken by pipeline operators to create, inspect, and enforce their own pipeline rights-of-way. Pipeline companies typically negotiate easements with individual property owners that give the pipeline operator authority to use the rights-
of-way for construction and operation of the pipeline, including the right to repair and maintain it. The authority of pipeline operators to control the use of the right-of-way is determined by the terms of the easement agreement; control does not extend to any property not covered by the easement/license.
Land use measures can reduce the risk of disturbing the pipelines by keeping human activity away from the immediate vicinity of the pipelines and by minimizing the exposure of those living and working near a transmission pipeline in the event of an incident. Some states set land use policy or mandate various kinds of land use and development regulation to protect against natural hazards.
Most local governments do not address pipeline issues. For those that do, there are few or no standards on which to base zoning ordinances and other development regulations. Some communities that have experienced pipeline incidents are implementing ordinances and other policies to reduce the perceived risks attributable to transmission pipelines, but these proposed ordinances do not appear to be based on a systematic assessment of risks and costs.
Although there is a lack of risk-based technical guidance for making land use decisions near transmission pipelines, the committee noted that much can be learned from hazard mitigation management techniques and strategies that have been adopted by state and local governments in other areas. These may be instructive in applying a risk-informed approach to land use measures for managing pipeline risks. At present, numerous local governments employ building standards, site design requirements, land use controls, and public awareness measures to reduce losses due to natural hazards (such as earthquakes and floods). However, state and local officials lack guidance for pipelines, other than rules of thumb and existing practice concerning appropriate setbacks.
While there is a general recognition that pipelines pose a hazard to people, property, and the environment, the extent of the danger is not well understood. Risk is inherent in the pipeline system—it can be reduced and managed, but it cannot be eliminated. Risk assessment practice attempts to answer the following questions:
What can go wrong?
How likely is it?
What are the consequences?
Regulatory approaches can be risk-based, risk-informed, risk-informed performance-based, or other variations of these. In the risk-based approach, decisions or regulations are heavily based on risk assessment calculations, without other considerations. Because such an approach places a heavy burden on risk computation, which may suffer from lack of data or models or imperfect consideration of scenarios, its application is limited. In the risk-informed approaches, risk insights are used in conjunction with other information, both quantitative and qualitative, in making safety decisions. Because risk-informed approaches allow for the logical structuring of decisions by including relevant factors, they are of more practical value.
Effective use of a risk-informed approach requires an understanding of the relevant factors and the relationships among these factors. In a risk assessment, which is a systematic and comprehensive approach, the likelihood of initiating events, as well as the likelihood of the various outcomes that may result from each initiator, is a concern. In assessing likelihood, a fundamental issue is the metric to be used. Likelihood can be expressed in terms of probability, and the combinations needed to yield the various outcomes can be computed by the use of logic and probability theory. However, the data that go into such calculations may entail significant uncertainties. Unless these uncertainties are explicitly acknowledged, the viability of the whole approach in decision making is compromised.
Local governments are increasingly faced with issues of land use. It appears beneficial for them to have available an easy-to-apply means for making decisions in a manner that allows flexibility in choosing the level of risk deemed appropriate. This is possible if the decision process is structured in a risk framework as outlined above. In addition, most local governments have neither the resources nor the in-house expertise to develop such a structure. Rather, a national-level effort is needed to develop a risk-informed approach and provide an appropriate level of abstraction that is easy to understand and use at all levels of government. Following implementation of selected options, system performance can
be monitored to determine whether risk control measures are effective. This iterative process can, over time, continue to reduce overall risk.
For the pipeline system, there are many stakeholders—policy makers, planners and system design experts, pipeline workers, local officials, property owners, residents, pipeline companies, and trade associations. They all should be knowledgeable about the risks so that informed guidance can be provided. Involvement and a shared commitment among these interested parties, effective communication, training, and procedures can make managing the risks associated with pipeline operations more effective. A well-thought-out risk management framework that measures the risks and identifies a set of risk mitigation alternatives would facilitate discussions among the stakeholders.
Pipeline incidents have potential for significant impact on life, property, and the environment.
Just as transmission pipelines pose a risk to their surroundings, so does human activity in the vicinity of pipelines pose a risk to pipelines. These risks increase with growth in population, urban areas, and pipeline capacity and network.
Land use decisions can affect the risks associated with increased human activity in the vicinity of transmission pipelines.
Pipeline safety and environmental regulation have generally focused on (a) the design, operation, and maintenance of pipelines and (b) incident response. They have not directed significant attention to the manner in which land use decisions can affect public safety and the environment.
For the most part, state and local governments have not systematically considered risk to the public from transmission pipeline incidents in regulating land use.
Risk-informed approaches are being used effectively in other domains (e.g., natural hazard mitigation, industrial hazard mitigation, nuclear reactor and waste disposal programs, tanker safety).
These techniques are also being used to address other aspects of pipeline safety (e.g., pipeline integrity), but they have not been used to make informed land use decisions.
Currently, decision makers lack adequate tools and information to make effective land use decisions concerning transmission pipelines.
Many different forms of pipeline easements are in effect, and the terms and conditions vary widely. To the extent that an easement lacks clarity, enforcement of the right-of-way is more difficult.
Encroachments and inappropriate human activity within the right-of-way can adversely affect pipeline safety. There appears to be variability in the quality and extent of inspections, maintenance, and enforcement of rights-of-way.
Conclusion 1. Judicious land use decisions can reduce the risks associated with transmission pipelines by reducing the probabilities and the consequences of incidents.
Pipeline safety is a shared responsibility. Land use decisions and control of activities and development near transmission pipelines may be undertaken by the pipeline operator, safety regulators, state and local officials, and the property developers and owners. Appropriate land use measures applied by local governments could bolster and complement a pipeline company’s efforts to protect the right-of-way and preclude uses that could pose a public safety risk.
Rational land use decisions that provide appropriate physical separation between people and pipelines could reduce the risk associated with the increasing numbers of people in proximity to transmission pipelines. Possible land use techniques include, for example, establishing setbacks; regulating or prohibiting certain types of structures (such as schools, hospitals, and apartment buildings) and uses near transmission pipelines; and encouraging, through site and community planning, other types of activities and facilities (e.g., linear parks, recreational paths) within or in the vicinity of pipeline rights-of-way. Utilization of such tools can be
legitimate exercises of the local jurisdictional police power if they are appropriately instituted, particularly if such exercises are grounded in objective, scientifically derived data.
Conclusion 2. It is feasible to use a risk-informed approach to establish land use guidance for application by local governments.
Various forms of risk-informed management of pipeline safety are already in wide use within the pipeline industry. Moreover, the integrity management regulations governing liquids and natural gas pipelines recently promulgated by OPS require private operators to prioritize enhanced risk-reduction efforts by using risk assessment.
The probability of failure of any transmission pipeline is a function of several distinct but interrelated factors including materials of construction, fabrication, corrosion, effectiveness of pipeline coatings and cathodic protection systems, pressurization, and depth of cover. Data and models are lacking for making precise predictions about specific lines, but estimates can be developed at an aggregate level and adjusted to account for local conditions. The possible consequences of an event could be estimated on the basis of the product carried, degree of pressurization, depth of cover, surrounding development, and other considerations. The appropriateness and acceptable cost of various measures to reduce probability and consequence could be derived from local values. Although such a risk-informed approach may be somewhat simplistic initially, it could be improved over time to a sufficient degree to help government officials regulate land use. The committee envisions an ongoing process that would involve risk assessment experts and stakeholders in the development, ongoing refinement, and application of such information.
Conclusion 3. The federal government could serve a useful role by providing leadership in the development of risk-informed land use guidance for application by local, state, and federal governments.
Pipeline safety is a national issue because the United States is traversed by 380,000 miles of transmission pipelines transporting numerous products, most of which could pose a threat to life, property, and the environment in the event of a pipeline failure. Because of the numerous
stakeholders concerned about pipeline safety and their divergent interests and the national breadth of the concerns, the federal government may be best positioned to initiate an open process of developing risk-informed guidance. OPS has already played a similar role in fostering and initially supporting the Common Ground Alliance. Land use policies relevant to transmission pipelines are made at all levels of government and need to be based on an unbiased, scientific analysis of the risks posed by pipelines to their immediate surroundings. Local governments generally lack the resources and incentives to undertake such an effort on their own. The advantage of consistent guidance across jurisdictional lines also argues for federal leadership.
Conclusion 4. There is clear evidence that guidelines can be developed that would assist in preserving habitat while maintaining rights-of-way in a state that facilitates operations and inspection.
As an adjunct to its main charge, the committee was asked to consider the problem of habitat loss when rights-of-way are initially cleared and subsequently maintained to allow for inspection, which is required by federal law. Right-of-way maintenance facilitates such inspection, usually conducted by aerial surveillance, and reduces the potential for tree roots to interfere with pipelines, which may contribute to failure. Rights-of-way can provide useful and functional habitat for plants, nesting birds, small animals, and migrating animals. In developed or urban areas, the ecological function of such rights-of-way may be useful but can be marginal, in large part because of the narrowness of the right-of-way and the already extensive habitat fragmentation. There is an overriding environmental benefit in effective inspection of pipelines to avoid incidents with consequent releases and environmental damage.
Recommendation 1. OPS should develop risk-informed land use guidance for application by stakeholders. The guidance should address
Land use policies affecting the siting, width, and other characteristics of new pipeline corridors;
The range of appropriate land uses, structures, and human activities compatible with pipeline rights-of-way;
Setbacks and other measures that could be adopted to protect structures that are built and maintained near pipelines; and
Model local zoning ordinances, subdivision regulations, and planning policies and model state legislation that could be adopted for land uses near pipelines.
Such a risk-informed guidance system should include three interrelated components:
A decision framework informed by risk analysis,
Guidelines based on the analysis, and
Alternative actions that could be taken on the basis of the guidelines.
Recommendation 2. The process for developing risk-informed land use guidance should (a) involve the collaboration of a full range of public and private stakeholders (e.g., industry and federal, state, and local governments); (b) be conducted by persons with expertise in risk analysis, risk communication, land use management, and development regulation; (c) be transparent, independent, and peer reviewed at appropriate points along the way; and (d) incorporate learning and feedback to refine the guidance over time.
Recommendation 3. The transmission pipeline industries should develop best practices for the specification, acquisition, development, and maintenance of pipeline rights-of-way. In so doing, they should work with other stakeholders. With regard to the specific maintenance issue of clearing rights-of-way to allow for inspection, the federal government should develop guidance about appropriate vegetation and environmental management practices that would provide habitat for some species, avoid threats to pipeline integrity, and allow for aerial inspection.