The consensus-building approach clearly enabled the diverse members of the Project Committee to broadly consider and work toward a common goal. This collaboration was built on mutual respect for one another’s respective specialties, knowledge and responsibilities. In working through this transparent process, participants developed trust in one another’s judgements. While the context of this project was an emergency caused by an oil spill, the same stakeholders would be involved in mitigating human health and environmental hazards associated with other emergencies, e.g., extreme weather or terrorism events. In this regard, this CERA added value to all-hazard preparedness in the Delaware Bay Watershed.
Working together, the Project Committee developed new CERA components for assessing risks from transportation-related Bakken and dilbit spills, described below. While the percentage of diluents added to bitumen varies for rail and pipeline transportation, the weathering behavior is the same and therefore this CERA considers dilbit as generally representative of diluted bitumen.
4.2. Response Actions
The Project Committee considered practical categories of currently available response actions that could be implemented during response to spills involving these oils, as well as their logistics limitations, and effectiveness considerations. The potential collateral damages that could result from implementing these response actions (e.g., physical trauma to organisms and habitats from shoreline cleanup, underwater recovery or physical contact methods of oil detection) were considered in the development of the conceptual models for each scenario, which identified the ways in which resources of concern could be exposed to potential hazards associated with the oil and response actions.
Response to spills of these crude oils involves two weathering timeframes: the initial flammability phase when light ends of the oils are present and fires could occur, during which the deployment of traditional spill response options would be pre-empted by first responder (fire fighter) actions; and the second, longer-term phase of responding to the oil on-water. For purposes of this CERA, pollution responders could become actively engaged in the initial 4–6 h after first responders (e.g., fire fighters) would have arrived on scene and might still be dealing with flammability risks. Recent incidents have resulted in significant fires involving Bakken oil, which has been known to re-ignite. Flammability is also a concern with freshly-spilled dilbit oil. During this emergency phase, public safety actions would take precedence over pollution response actions. The behavior of the oil will begin to change due to weathering after the initial 4–6 h.
Next, the CERA considers the weathered oil behavior approximately four to seven days after the emergency phase during which oil could still be found on the water surface and be recoverable using traditional pollution response techniques. Toward the end of this timeframe, the residual bitumen component of dilbit oil would likely begin to pick up sediment in the water column and sink below the water surface, either in the water column or settle on the bottom. The time scales associated with response actions are not absolute; rather they represent a range of hours and days that generally align with important oil weathering and behavior changes that ultimately would influence decisions about potential response actions.
For both of these crude oils, oil recovery on-water is difficult after the oil weathers. Bakken oil is a light crude oil; following rapid evaporation of light ends, the remaining components naturally disperse into the water column, making recovery from the water generally impractical. Dilbit oil, on the other hand, is comprised of heavy oil tar sands mixed with diluents to facilitate its transportation. When initially spilled, the light fractions in the diluted bitumen begin to evaporate. After a few days, residual heavier components may be exposed to sediments in the water column and no longer float, making it more difficult to track and recover.
The following categories of response actions were used in assessing the risks associated with responding to Bakken and dilbit oil spills in the five transportation-related scenarios:
Natural attenuation with monitoring (NAM)
Fire—Let burn and controlled burn (both in-situ)
Fire—Extinguishing agent and methods
No Fire—Vapor suppression
No Fire—Oil spread control (on-land, on-water, and underwater)
No Fire—On-water recovery and underwater recovery
No Fire—Resource protection (on-water and on-land)
No Fire—Shoreline clean-up
No Fire—Oil detection/mapping (physical-contact methods)
No Fire—Oil detection/mapping (remotely-observed methods)
The overall list was categorized to better align with the response categories of previous ERAs and to facilitate evaluating their risks. These general categories provided a common framework for the workgroup participants since specific response actions could vary among the five scenarios, e.g., some on land, some on water, and presence or absence of ice. The following section defines each possible response action and lists some points regarding logistical considerations, limitations, and considerations that influence its effectiveness in mitigating threats presented by spilled Bakken and dilbit oil. During the risk characterizations, participants discussed additional, more detailed aspects of the response actions.
4.2.1. Natural Attenuation and Monitoring (NAM)
Natural attenuation relies on natural processes to decrease or “attenuate” concentrations of contaminants (oil) in soil, groundwater, and water. NAM can also be used when the oil is not recoverable, more environmental damage will occur from the response actions, or effective spill response resources are not available. NAM may require extensive monitoring via sampling and other methods, a network of trained observers, detailed sampling protocols, and other unique underwater sampling methods for sinking oils (e.g., dilbit crude oil if it sinks after the majority of light fractions evaporate). Monitoring typically involves collecting soil, groundwater, and water samples to analyze them for the presence of contaminants (oil) and other site characteristics. Some limitations/complications of NAM include: difficulty locating/tracking dilbit if it sinks, potential significant substrate environmental impact if residual dilbit oil sinks, fisheries closings, and public dissatisfaction with the oil spill response. The effectiveness of NAM depends on a multitude of factors such as oil type, ambient weather, and other environmental considerations. Attenuation may be most prudent for Bakken crude oil. Because dilbit is more persistent, it may not be a good candidate for attenuation on land. In responses involving NAM, monitoring would be required (visual monitoring at a minimum) for both oil types; long-term monitoring of spilled oil is most effective and practical on land, compared to a spill in water.
4.2.2. Fire—Let Burn and Controlled Burn (both In-situ)
Allowing product to burn in-situ
is another possible response action. Given the five scenarios, CERA participants considered allowing rail cars to burn themselves out, or control the burn to reduce environmental impacts of the spilled oil. Although (intentional) controlled burning in situ
was discussed and remained as an option, fire boom would have to be available and the logistics and regulatory approval could preclude its implementation. Air quality issues play a significant role with intentionally burning Bakken oil, e.g., concerns about breathing in the toxins that are in the resultant smoke plume. Example logistical considerations for this response action that must be addressed include:
How and where to obtain and apply water-cooling streams?
Are current fireboats sufficient and able to respond?
Can first responder and public safety air monitoring be deployed?
Can adequate protection of exposed structures be attained?
Potential limitations of this response action include sufficient access to water supply, frac tanks, high-flow fire pumps and nozzles. The effectiveness of this response action is highly dependent upon the ability to get close enough for effective water cooling, as there is a great potential for “heat-induced tear” in the rail car's shell resulting in a rapid release of vapor and violent fire.
4.2.3. Fire—Extinguishing Agent and Methods
This response action includes the strategies and tactics that use extinguishing agents, including firefighting foam, and the people, equipment and other resources used to extinguish a crude oil fire. Extinguishing agents put a fire out by disrupting one of the four pieces of the fire tetrahedron. Logistical considerations include foam availability and applicability given the incident-specific conditions and consideration of adjacent rail cars or shipboard tanks that must be addressed when utilizing extinguishing agents. Some limitations of using extinguishing agents include:
The ability to access, in a timely manner,
Sufficient quantity of foam and water,
Dry chemical agents,
Fire boom, and
Fire boats with the necessary high-volume fire pumps and nozzles.
Additionally, fighting crude oil fires requires highly skilled and specialized personnel. This response action is very effective if the required resources arrive quickly, and the methods are applied properly to the developing situation. This is especially critical before adjacent rail cars are heated to the point of shell plate failure and catch fire.
4.2.4. No Fire—Vapor Suppression
This strategy uses vapor suppression agents, i.e., firefighting foam, to reduce and/or blanket the vapors being released from pooled crude oil in order to reduce the risk of fire and to provide a safe working environment for the first responders and the surrounding public. Examples of logistical considerations include sufficient quantity of foam, regulated products under Subpart J of the NCP (such as herding agents and encapsulators), absorbents, intrinsically-safe vacuum pumps/trucks, personal protective equipment (PPE), and air monitoring equipment. This strategy is not without limitations, because the application of firefighting foam on waters of the US, and where the runoff would enter navigable waters, involves water pollution regulatory issues. Additionally, depending upon the scenario and amount of product spilled, a large coverage area may be required to suppress the vapors. This response action is effective for pooled crude oil in containment (e.g., oil contained by boom, drainage ditch, or small creek).
4.2.5. No Fire—Oil Spread Control (On-Land, On-Water, Underwater)
This response action includes the strategies and tactics that control the spread of oil, and the people, equipment and other resources used to contain the oil. Examples of this strategy include containment and/or deflection boom, sorbents, pneumatic curtains, turbidity curtains, dams/dikes, interceptor trenching, underflow dams, and pre-staged boom. Some limitations of utilizing this action include ensuring a sufficient quantity of boom, sorbents, and other materials given the amount spilled, current weather conditions, and the type of product. Additionally, the speed of deployment is critical to reduce the spread as winds, tides/currents; and ice can hamper response actions. Controlling the spread of submerged oil is a unique and challenging task, and may require non-typical oil spill response techniques. These response actions can be very effective if deployed correctly and in a timely manner. For underwater oil spread control, turbidity, silt, and pneumatic curtain effectiveness may be impacted by surface and subsurface currents and tidal exchanges, and are sometimes difficult to position and hold in place with changing environmental conditions. Additionally, extreme tidal ranges, which may expose mud flats at low tide will decrease the efficiency of this response action due to the difficulty of deploying and maintaining floating boom under these conditions.
4.2.6. No Fire—On-Water Recovery and Underwater Recovery
This response action is used to recover spilled crude oil from the water’s surface or subsurface, for the purpose of preventing oiling and minimizing damage to sensitive shoreline resources and habitats. Example resources used to enact this strategy include skirted booms, self-propelled skimmers, stationary skimmers, and advancing skimmers (brush, drum, weir, and Dynamic Inclined Plane/DIP), dredges (hydraulic, clam shell), trawls, nets, and vacuum systems. Both on-water and underwater recovery is limited by a number of factors including the type of skimmer, which must be selected for the type of oil and the weather conditions, and the ability to access the oil. Recovery amount is dependent upon many factors, one of which is encounter rate, or the area of oil that an individual skimmer can encounter over a period of operational time e.g., in 12 h per day. Brush skimmers have been shown to be more effective and efficient for heavy oils like dilbit; assuming the oil remains floating. DIP, weir, filter belt, disk, and drum skimmers have been shown to be more effective for recovering light oils like Bakken. Size and configuration of these skimmers must be commensurate with the weather and sea conditions to achieve maximum effectiveness.
Additionally, collection booming, nets, trawls, pumps, dredges, divers, vacuum systems, airlifts, and bottom trawls can be used to recover heavy oils, i.e., those with a specific gravity equal to or heavier than water from being produced that way, e.g., some #6 oils, or attains a specific gravity equal to or heavier than water through physical or chemical changes (weathering). After the lighter components of dilbit evaporate, the heavier and more viscous components remain on the water. Under certain conditions, the remaining oil can pick up sediment from the water column resulting in increased specific gravity. An increase in specific gravity can result in oil that becomes neutrally buoyant or heavier than water, causing it to submerge below the water’s surface. Oil in this state is very difficult to locate and recover. Diver effectiveness is impaired by low visibility, and differentiating oil from mud. Recovery of submerged oil in rivers and estuarine areas with heavy sediment load and currents is especially challenging. The use of remote sensing and GPS integrated systems can increase the effectiveness of underwater recovery.
4.2.7. No Fire—Resource Protection (On-Water and On-Land)
This response action involves protecting sensitive areas by deploying protection strategies using boom, which are physical barriers used on land or water (floating), made of plastic, metal, or other materials, which slow the spread of oil and keep it contained. Boom can also be utilized to deflect oil away from sensitive areas, to include water intakes, historic sites, and critical fishery areas. Types of floating, skirted boom (cylindrical float at the top and is weighted at the bottom so that it has a “skirt” of varying dimensions under the water) considered include: 12” boom for protection/deflection due to shallow water in rivers and creeks, and ease of use; 18” boom used for deeper water areas like bays and inlets; and larger (24”+) boom used for coastal and offshore areas. A turbidity/silt curtain can be used to limit submerged oil movement. Other protection methods include pneumatic curtains, dams/dikes, interceptor trenching, underflow dams, and shore-seal boom. Although there are many types of equipment and tactics to protect sensitive areas, shoreline type, oil type and volume, topography, porosity, and shape will limit the effectiveness of protection strategies. Stakeholders should recognize that protection of 100% of shorelines and sensitive areas is impractical, if not impossible. The tidal range and shallowness of some creeks and tributaries expose the mud flats at low tide; therefore restricting protective boom deployment to higher-tide hours only, and may impact placement of protection boom in general. Additionally, current and tide necessitates that boom be tended at every tide cycle. Protection strategies for floating oils have been demonstrated to be effective, when anchored properly and tended round-the-clock. It is important to note that mechanical protection of large areas, e.g., around or in front of islands or in across the mouth of a bay, is much more difficult that lay people imagine. Effective protection strategies for non-floating oils are even more difficult to implement.
4.2.8. No Fire—Shoreline Clean-up
The use of this strategy involves the removal of oil from the shoreline for long-term disposal elsewhere to prevent further or introduction of contamination to sensitive areas and habitat. Examples of this response action include mechanical recovery systems (vacuum trucks, storage tanks, sorbent, hand tools, laborers), and NCP Subpart J surface washing agents. To reduce the amount of recovered oily waste for disposal, pre-spill impact debris removal is advised, which could be quite extensive depending upon the location. The specific shoreline cleanup method selected will be based on shoreline type and oil type; shoreline access, and consideration that habitat may be affected detrimentally by the cleanup activity (foot traffic or machinery) itself. The effectiveness of shoreline cleanup depends on many factors: oil type (heavy vs. light), type of shoreline and the amount of debris present, and the fact that tidal ranges and cycles can significantly impact responder work schedules (e.g., daylight hours and total time shoreline is exposed at low tide). A shoreline cleanup response requires close coordination between the personnel conducting response operations and Shoreline Cleanup (or Countermeasure) Assessment Technique (SCAT) teams to determine extent of shoreline contamination, cleanup priorities, and acceptable methods for removing the oil. Depending on the magnitude and location of the spill, shoreline cleanup can be the most logistically demanding portion of an oil spill response. Shoreline cleanup can have a high degree of collateral damage.
4.2.9. No Fire—Oil Detection/Mapping (Physical-Contact Methods)
Oil detection and mapping includes the strategies, methods, and resources used to detect oil by physically sampling habitats to track oil movement, location, physical properties, and extent of contamination. Examples of this response action include collecting water, soil and air samples, and establishing monitoring stations and other oil detection sensors. Examples of sub-surface measuring techniques include using trawls and underwater sentinels, crab pots, snare samplers, Vessel Submerged Oil Recovery Systems (VSORS), and remotely-operated vehicles (ROVs). These methods can result in physical trauma of the habitat, and associated organisms. There are many limitations to this response action, especially if the oil is submerged, such as the need to rapidly develop a complete and defensible sampling protocol and procedures to adequately check potentially-impacted areas, given that tides, winds and currents spread oil quickly. Determining sampling locations may be difficult for submerged oil, especially if the oil is mobile. Effectiveness of these response actions is limited by the lack of a full suite of effective technologies to detect oil and map its extent of contamination in all subsurface environments (water column or benthos). Currently, some subsurface mapping methods exist, but this remains an active research and development area.
4.2.10. No Fire—Oil Detection/Mapping (Remotely-Observed Methods)
This response action involves the use of remotely-operated sensors and human vision to detect and monitor the movement of oil in the environment from a distance, in this case, on the water surface or subsurface. Examples of remote sensing include visual observation via overflight and technological sensors including laser sensors, infrared, and photobathymetric sensors. On-water remote sensors include sonar scans (e.g., side-scan, multi-beam, etc.) laser fluoro-sensors, and underwater visual detection by divers or remotely operated vehicles and autonomous underwater vehicles. Limitations of these techniques include weather interference, adequate detail to inform decision making, e.g., thickness of oil slicks and mistaking oil for other substances), availability of equipment and operators, data interpretation, and the development of comprehensive sampling protocols and procedures Effectiveness of these response actions is limited by the lack of a full suite of effective technologies in all ambient conditions (ice, poor visibility in air or in the water) to detect oil and map its extent of contamination in all surface and subsurface environments (water column or benthos). Some methods to detect oil remotely this do exist, but this also remains active research and development area. There is usually little to no collateral damage with these methods but their effectiveness can also be limited by incident-specific conditions.
4.4. Risk Ranking Matrix
The CERA uses a risk ranking matrix to assign levels of concern about the potential severity and duration of impacts caused by the spilled oil, if left to attenuate naturally, or as addressed by the individual response actions listed in Section 4.2
. After reviewing the risk matrix from previous CERAs, a modification was adopted for evaluating the relative levels of concern of the impacts of Bakken or dilbit oils in the five scenarios. The Y-axis of the risk ranking matrix shown in Figure 6
, was used to describe the collectively perceived ecological severity, rather than the percent loss/reduction of the specific natural resource based on a measured endpoint that is not site-specific/species-specific/community-specific to the instant scenarios and were not always applicable to the selected scenarios. The X-axis in Figure 6
describes Recovery Time over arbitrary, but participant-consensus based, periods of time. Use of the matrix is qualitatively dependent on the individual participant’s experience and perception with respect to the complexity of the habitats and species present. Notwithstanding, the final ranking of risk is achieved through consensus of the participants thereby arriving at an estimation of the risk that is acceptable to multiple parties.
Participants evaluated potential risks of the oil and response actions and assigned levels of concern using the best available information from literature, past experience with oil spills in an area, e.g., the 2004 oil spill from the M/V Athos-1 in the Delaware River, and their knowledge of resources in the area, rather than additional data collection or field studies. As can be seen in the risk matrix, the groups used alphanumeric scores to scale the anticipated impact severity and recovery time. After developing the scaling, color coding was used to indicate the summary levels of concern. The resulting risk scores represent a participant consensus that severity and duration of consequences were likely to occur in the given scenario.
Risk is defined as the probability of an impact occurring. Participants qualitatively considered if there was a high, medium, or low probability of the impact occurring, and then determined the severity and the duration of the impact. During an incident, responders tend to consider and decide about impacts that are relatively short-term and based upon what was learned from previous response events, e.g., it is better to protect marshes to avoid having them oiled because of the longer-term severity and duration of oil impacts in those environments. The response community recognizes that protecting marshes from oiling is a best response management practice; this knowledge proactively and affirmatively guides many preparedness and response decisions. For any T/E species, any harm qualifies as a take under the Endangered Species Act, Section 7, and Incidental Take of Endangered and Threatened Species in U.S. Lands or Waters. Being listed on the ESA makes it illegal to take. Take is defined as harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, collect, or attempt to do these things (50 CFR § 3(19), 2009) any of these protected species, whether endangered or threatened or adversely modify or destroy designated critical habitat under Section 9—Prohibited Acts. These prohibitions under Section 9 are not automatic for threatened species; the USFWS and NMFS must conduct a Section 4
process to address threatened species. and is significant. As generally applied in this ERA, non T/E plants would recover in four to five years and non T/E fish would recover in one to two years. The ranking of red does not mean to stop response actions, but rather to review and assure that response actions would not adversely affect the species of concern, that the risk is recognized, and deemed appropriate to decision makers, including resource managers.
The definitions of ecological severity used by participants in assessing risk in this CERA are:
Discountable: Impacts are considered negligible, trivial, or a minor inconvenience.
Impaired: Short-lived modestly adverse impacts that alter habitats or life cycles.
Significant: Sustained and substantive adverse impacts that potentially lethal or highly damaging to a natural resource(s).
Dysfunctional: Long term damage that prohibits a natural resource from living, reproducing, or providing an ecological service(s).
The ranking measures were also appropriate for characterizing human health risks. The impact from a drinking water ban would likely be considered Dysfunctional in severity; inhalation and dermal impacts might be ranked as Significant.
Duration of impact begins from the time of the oil discharge. Severity takes into account the significance of individual organisms relative to the scale of population. For example, if an organism has recovered 70% in about one year, but would take 10 years for 100% recovery, then the risk could be ranked as significant, in the one to four-year duration. Local populations that could be killed by a spill would receive a dysfunctional score. Freshwater mussels, for example, if wiped out by oiling in a creek, will not recover for 50–100 years. This would equate to a risk of a dysfunctional impact. Generally, participants considered populations of organisms at the local scale, and assumed no impacts on a regional or national scale for that species.
4.5. Risk Characterization
The conceptual models were used first to clarify the pathways of exposure and the types of hazards between the spilled oil and seasonally-present ecological resources. The risk matrix was first completed by each workgroup to characterize the risks to resources of concern from the oil only, i.e.
, no response action, except for natural attenuation and monitoring (NAM). Next, participants compared the potential risks of each category of response actions to the risks associated with the spilled oil left in place to attenuate, plus monitoring via sampling. Relative risks were compared in this way:
If using a response action is likely to improve the outcome, the score is a lower alphanumerical value than the spilled oil (NAM).
If using a response action is likely to worsen the outcome, the score is a higher alphanumerical value than the spilled oil (NAM).
Selecting appropriate response strategies for each of these oils takes into account their behavior in the environment before and after weathering. For this reason, Figure 7
and Figure 9
display the summarized risks for the oils and strategies for the initial spill of oil before it has a chance to weather and Figure 8
and Figure 10
display the summarized risks for the oils and strategies for the oil after it has weathered. For convenience, a row that highlights the transportation setting (i.e.
, urban, creek, river or bay) of each of the scenarios has been added to the summary tables.
Bakken and dilbit oils present flammability hazards during the early stages of a spill, such as the 2013 derailment in Lac-Megantic, Canada that resulted in Bakken oil fire in the center of town and loss of life. The risks to human health and safety and social-economic resources from a fire, as well as firefighting foam, as highlighted in Scenario 1, were scored as a moderate level of concern (yellow) assuming that safety measures were successful, e.g., PPE for workers and other protective measures for the public, such as safe distance from fire and shelter in place away from the smoke plume. For human health and safety, the levels of concern from the oil only and for other response actions were scored as low (green).
The red ranking (high level of concern) represents a need for follow-up action by the USCG and other agencies in the area to more fully address whether certain response actions will be allowed and if so, under what circumstances, e.g., in certain seasons or under specific conditions. The red ranking, highest relative risk, is not intended to prevent or stop response actions, but rather to prompt further review and assure that response actions would not adversely affect the resources of concern. In this CERA, participants generally assigned higher levels of concern about the ecological risks associated with a spill of dilbit oil compared to a spill of Bakken crude oil.
The gray cells scored “Not Applicable” refer to the absence of either the resource of concern in a scenario or the lack of pathway for exposure to the hazard presented by the oil or type of response action. For example, in Scenario 3, which involves a spill of Bakken oil in the upper Delaware Bay in winter, during the first 4–6 h, the risk to shorelines and benthos were scored as Not Applicable because the oil would not reach those environments in that time frame.
4.5.1. Bakken Oil Spill Risks
Scenario 1 occurs at a rail crossing within Philadelphia’s urban setting; Scenario 2 involves a barge in the middle of the Delaware River near Pea Patch Island, an ecologically and culturally-sensitive resource; and Scenario 3 involves a tanker in the open water of upper Delaware Bay.
In general, the workshop participants from Scenarios 1, 2, and 3 found that the “No Response other than monitoring” option was considered of limited or moderate level of concern when deemed appropriate for the scenario conditions, both at the 4 to 6 h response frame or at four to seven days post discharge. In most cases, the participants found that there was very little change in concern levels when considering the various response action versus the NAM action. Although some of the levels of concern did increase from low to moderate (green to yellow), this increase in concern did not necessitate a change in response options. The highest level of concern in the urban, freshwater scenario (1), was with the use of extinguishing or vapor suppression agents in the intertidal zone for both the initial response and over the four to seven day response times.
Overall, the highest level of ecological concern (red) in these scenarios occurs from the risk of the use of firefighting foam or vapor suppression agents to threatened/endangered species, which might be present in Scenario 1 intertidal shoreline. The use of foam in this area increased the risk (yellow) over the presence of oil only (green). The runoff from firefighting foam, if applied, could present both human health and ecological risks. Many earlier formulations of fire suppression foam contain perfluorochemicals (PFCs
) that were used to improve smothering capability; however these formulation are being phased out in the US [48
]. Specific actions that decreased or increased the risks to resources of concern over the oil alone, i.e.
, NAM, are discussed below.
In the initial 4–6 h after a Bakken spill occurs in these scenarios, the response actions that positively change, i.e., decrease the risk (change a yellow to a green score) compared to the NAM are: Scenario 1—oil spread control, on-water recovery, resource protection, shoreline cleanup, and remotely observed oil detection/mapping in the mid-water habitat (Scenario 1). In the initial 4–6 h after a Bakken spill occurs in these scenarios, the response actions that negatively change, i.e., increase the risk (change a green to a yellow score) compared to NAM are: Scenario 1—oil spread control, on-water recovery, resource protection, shoreline cleanup, and remotely observed oil detection/mapping in natural terrestrial shorelines.
In Scenarios 2 and 3, implementing response actions does not noticeably decrease ecological risks compared to the risk of NAM. After the oil has been in the environment for four to seven days, much of the Bakken oil would have weathered, leaving a light residual oil staining on shorelines, and the intertidal portion of the shoreline, which could be below the water surface (surface water or mid-water column habitats) during high tide. After the oil has been in the environment for four to seven days, the response actions that positively change, i.e., decrease the risk (change a yellow to a green score) compared to NAM is: Scenario 2—implementing on-water oil recovery near intertidal shorelines. After the oil has been in the environment for four to seven days, the response actions that negatively change, i.e., increase the risk (change a green to a yellow score) compared to oil only are: shoreline cleanup in artificial shorelines and natural terrestrial shorelines in Scenarios 1 and 2.
4.5.2. Dilbit Oil Spill Risks
Scenario 4 occurs at a rail crossing over Mantua Creek in New Jersey; Scenario 5 involves a barge in the middle of the Delaware River near the Marcus Hook Anchorage. Generally, the ecological risks associated with spilled dilbit oil and the anticipated response actions for the two scenarios are either moderate or high level of concern, especially if T/E species are present in contaminated areas.
As with Bakken oil, the highest level of concern (red) in these scenarios occurs with threatened/endangered species, which may be present and could be impacted by the oil and/or response actions. In these scenarios, T/E species (e.g., Atlantic sturgeon to sea turtles to bald eagles) might be present and at risk in all environments except artificial shorelines.
In general, the workshop participants from Scenarios 4 and 5 found that the NAM option provided a moderate to high level of concern, both at the 4 to 6 h response timeframe to four to seven days post-discharge. In most cases, the participants found that there was very little change in concern levels when considering the various response action versus the NAM action. Some of the levels of concern did increase for response actions over the 4 to 6 h timeframe to the four to seven day period from low to moderate (green to yellow). The high level of concerns (red) were scored for scenario 5 regarding the use of most response options deemed applicable for use in the intertidal, mid-water, and benthic zones for both the initial response and over the four to seveb day response times. Similar concerns were also expressed for Scenario 4 when considering the risk of shoreline clean up and oil detection/mapping methods for the intertidal and midwater zones. Specific actions that decreased or increased the risks to resources of concern over the oil alone, i.e., NAM, are discussed below.
In the initial 4–6 h after a dilbit spill occurs in these scenarios, the response actions that positively change, i.e., decrease the risk (change a yellow to a green score, or a red to a yellow score) compared to NAM are: Scenario 5—oil spread control and on-water recovery in artificial shorelines and at the water’s edge (0 meters of the mid-water habitat); and resource protection in intertidal shorelines. In the initial 4–6 h after a dilbit spill occurs in these scenarios, NAM actions negatively change, i.e., increase the risk (change a green to a yellow score, or a yellow to a red score) compared to the presence of the NAM action only.
It is important to note that in some habitats, oil detection and mapping methods (if physically disturbing) were scored as a higher risk (red) than oil spread control, on-water recovery and resource protection to natural vegetated shorelines, intertidal shorelines, and mid-water habitats (yellow or green). Remote sensing methods would present a low (green) ecological risk. Participants recognized that available methods to detect and recover submerged dilbit oil are lacking in effectiveness.
Workgroup participants noted that on-water oil recovery in the earliest stage after release is the most important response action to prevent the oil from spreading out and expanding the extent of contamination, e.g., into the Delaware River, and contaminating larger shoreline and benthic habitats and organisms. This oil begins as a crude oil which flows but weathers to a heavy oil product that resembles #6 oil that will be extremely tacky and adhesive. The oil is expected to behave differently as it weathers; it could behave as one type of weathered product and a different type a few hours later. After the light ends have volatized, the residual product will adhere to whatever it contacts. From an environmental standpoint, this is a significant challenge for onshore cleanup and wildlife rehabilitators to avoid if at all possible. It will take time to experiment (trial/error) with emerging ideas and techniques and develop new response/restoration best management tactics to manage dilbit releases. This was the situation during the 1989 M/V Presidente Rivera oil spill on the Delaware River, during which the set of response tactics varied in the same day. In the morning when the oil temperature was below the pour point and did not flow on beach sand, it could be recovered with a pitchfork, for example. However, in the afternoon when the sunlight warmed the oil stranded on the sand and it flowed, it could no longer be picked up, and sorbent booms were needed to contain it.
After four to seven days, much of the dilbit oil would have weathered to the point that the light fractions had evaporated, leaving the heavier, persistent bitumen in the environment, available to pick up sediments in the water column and sink to the benthos, or on shore. After the oil has been in the environment for four to seven days, the response action that positively changes, i.e.
, decreases the risk (change a yellow to a green score) compared to the remaining oil (NAM only) are:
Scenario 4—controlled in-situ burning in natural terrestrial shorelines, intertidal shorelines, and the water’s edge of the mid-water column.
Scenario 4—oil spread control, on-water recovery, resource protection, shoreline cleanup in natural terrestrial shorelines
Scenario 5—resource protection in intertidal shorelines.
Scenario 5—oil spread control, on-water recovery the water’s edge of the mid-water column.
After the oil has been in the environment for 4–7 days, the response actions that negatively change, i.e., increase the risk (change a green to a yellow score) compared to NAM are:
The focus of this CERA was to evaluate different response actions to spills involving Bakken and dilbit, which have become part of the USCG’s evolving responsibilities in the recent domestic energy renaissance, particularly in the Delaware Bay Watershed. Drawing on a cross-section of the local oil spill response community the ecological impacts of spilled oil and spilled oil plus a response action were evaluated to predict the severity and duration of adverse impacts to natural resources of concern. Once oil spilled into the environment one objective of the emergency response community is to react in such a manner as to minimize or prevent additional harm to the environment. CERA promoted agreement among and between the risk management team, stakeholders, and interested parties towards the common goal of successfully planning for and responding to oil spills in such manner as to transparently consider the conservation of natural resources for the benefit of human uses and wildlife habitat.
This CERA is consistent with this concept of conservation of natural resources while allowing multiple uses. Further work is needed to address domestic energy transportation needs that are compatible with and provide protection of natural resources and the human and ecological services they provide.