The National Sea Grant Law Center


  • North Carolina Rejects Proposal to Conduct Seismic Airgun Surveys off the North Carolina Coast

  • July 31st, 2019 — by Bryce Burgwyn — Category: Coastal Management

  • North Carolina has objected to a federal permit granting WesternGeco, LLC authorization to conduct seismic airgun surveys in federal waters off the Atlantic Coast of North Carolina. In making its decision, the North Carolina Division of Coastal Management reviewed input from subject matter experts, state agencies, and the public. North Carolina deemed WesternGeco’s proposal inconsistent with the relevant enforceable policies in the North Carolina Coastal Zone Management Program.

    The Coastal Zone Management Program
    The federal Coastal Zone Management Act (CZMA), 16 U.S.C. §1456, allows states the opportunity to analyze permit applications for consistency of all proposed activities with their respective state Coastal Management Programs. Federal permits for activities on the Outer Continental Shelf (OCS) adjacent to North Carolina state waters must be consistent to the maximum extent practicable with the enforceable policies of the federally approved North Carolina Coastal Management Program. North Carolina’s coastal zone management program consists of the Coastal Area Management Act, Dredge and Fill Law, and Chapter 7 of Title 15A of North Carolina’s Administrative Code. North Carolina’s Coastal Management Program goals include the preservation of the recreational value of the coastal zone, balanced use and preservation of natural resources, economic development of the coastal zone, and protection of the public trust rights in the lands and waters of the coastal zone. Under General Statute 113A-120, the state will deny any application for a permit that is inconsistent with state guidelines or would contribute to cumulative effects inconsistent with the program goals.

    North Carolina’s Objections to Seismic Airgun Surveys
    Most of North Carolina’s objections to seismic airgun surveys stem from the high-intensity blasts of sound produced by seismic airgun equipment. WesternGeco’s project proposal includes an array of multiple airguns, towed behind a survey vessel, firing 225-260 decibel bursts of sound approximately every 10-15 seconds. Sound waves with the same intensity in water and air measured in watts per square meter have relative intensities that differ by 61.5 decibels, due to the different densities and characteristics of air and water. The intensity range of the seismic airgun blasts correlates to 163.5-198.5 decibels in air. For purpose of comparison, according to the National Institute of Health, sounds with intensities greater than 85 decibels cause permanent hearing damage in humans. Humans experience pain when exposed to sounds with intensities of 120 decibels. The sound intensity of a grenade exploding is 160 decibels. The sound generated by the airguns penetrates deep into the sea floor and returns to a 10-kilometer-long streamer towed behind the vessel, collecting seismic data that can be used to identify subsurface oil and gas reservoirs. The sounds produced by the surveys can travel vast distances through water. NOAA has recorded the pulses of sound produced by seismic airguns with hydrophones placed over 1,500 km from a survey location. The decibel scale is logarithmic, and an increase of 10 decibels implicates a tenfold increase in the intensity of a sound.

    In its letter to WesternGeco, North Carolina presented several well supported objections to the proposed surveys. The coastal waters of North Carolina are a valuable economic resource to the state for commercial fishing, recreational fishing which includes a large charter fleet and offshore fishing tournaments, and SCUBA diving. The state expressed concern that interference with normal fish behavior, including displacement from their usual habitats and reduction in overall abundance, will decrease catchability. The state cited a study which demonstrated that a single airgun producing sounds of lower intensity than those in WesternGeco’s proposal caused a 60% decrease in zooplankton, which forms the base of the food web that supports economically important species. The list of important commercial species from BOEM’s environmental impact statement was incomplete, and WesternGeco’s assessment of environmental impact failed to consider several important fisheries. The assessment also failed to consider essential fish habitat for state managed, economically important species. Spawning activities for commercially important species occur year-round, and cumulative survey activity may decimate populations by destroying larvae and eggs.

    In response to WesternGeco’s assertion that all survey activity takes place in federal waters 19 miles from the boundary of state waters and therefore does not directly impact state resources, North Carolina emphasized that many fish species spend portions of their life cycle in nearshore waters and portions in federal waters. Furthermore, as evidenced by NOAA’s recording, the sound generated by the survey equipment travels great distances underwater. North Carolina also expressed concern that WesternGeco’s plan to use chase boats to enforce an exclusion zone around the 10 km long streamer will impede access to fishing grounds and dive sites, and especially impair offshore fishing tournaments, which are crucial to coastal North Carolina’s seasonal economy. The precise impact of seismic airguns on marine life is difficult to quantify or describe until after harm has occurred, since most of the relevant impact would occur far from human observation. However, based on the probability of significant adverse impacts of fish and marine food webs, sensitive fish habitats, commercial, recreational and subsistence fisheries, and the coastal economy, North Carolina deemed that WesternGeco’s proposed survey is inconsistent with the enforceable policies of the CZMA.

    The Bureau of Offshore Energy Management’s Changed Approach to WesternGeco’s Permit
    The federal Bureau of Offshore Energy Management (BOEM) had previously denied WesternGeco’s permit application in January 2017. In a letter to WesternGeco explaining the denial, BOEM stated that the permit was denied because of an Obama-era order, which removed the Atlantic from consideration for oil and gas leasing until 2022, and therefore seismic survey data was not needed or may be outdated by the time the Atlantic coast was considered for drilling. In May 2017, BOEM rescinded its denial, citing Department of the Interior Secretary’s Order 3350, which implemented the Trump administration’s “America-First Offshore Energy Strategy.” BOEM stated that under that order, it was directed to reconsider appealed, new, or resubmitted applications for Atlantic surveys. Although the Atlantic coast still may not be considered for drilling, BOEM now claims that updated seismic surveys are needed to determine the extent of oil and natural gas resources on the OCS to determine the fair market value of future leases.

    Next Steps
    North Carolina’s objection has stopped to WesternGeco’s permit for now. On July 10th, WesternGeco appealed North Carolina’s objection. To grant an override request, the Secretary of Commerce must either find that the state is wrong and WesternGeco’s proposed activities are consistent with the objectives or purposes of the CZMA, or that WesternGeco’s proposed activities are necessary in the interest of national security. North Carolina is not the only state trying to prevent seismic airgun surveys. With BOEM is currently reviewing permit applications from five companies along the Atlantic Coast, other coastal states face similar concerns. A bipartisan coalition of ten coastal states led by South Carolina, including Maine, Massachusetts, Connecticut, New York, New Jersey, Maryland, Delaware, Virginia, and North Carolina, have brought a lawsuit (South Carolina Coastal Conservation League v. Ross, 2:18-cv-03326, U.S. District Court, District of South Carolina (Charleston)), seeking to block BOEM from issuing any Atlantic seismic survey permits.

  • Bryce Burgwyn
    Research Associate

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