Public Release: 

Report identifies options for lowering risk of failure of undersea bolts on offshore oil rigs

A new report from the National Academies of Sciences, Engineering, and Medicine identifies strategies for improving the reliability of bolts used in offshore oil and gas drilling rigs.

National Academies of Sciences, Engineering, and Medicine

WASHINGTON -- A new report from the National Academies of Sciences, Engineering, and Medicine identifies strategies for improving the reliability of bolts used in offshore oil and gas drilling rigs, thereby reducing the risk that a bolt failure could cause a spill of oil, drilling fluids, or natural gas into the environment. Although the oil and gas industry has made important advances in improving the reliability of bolts, there are multiple opportunities for the industry and the U.S. Department of the Interior's Bureau of Safety and Environmental Enforcement (BSEE) to work together to further improve reliability and safety culture, the report says.

Bolts and other fasteners are an integral part of undersea equipment in offshore oil rigs, including for critical pieces of safety equipment such as blow-out preventers (BOP). No major oil spills have resulted from the failure of a bolt or fastener, but there have been minor oil releases and near misses caused by unexpected bolt failures. Such incidents illustrate a compelling need for augmenting the regular inspection with an industrywide continuous monitoring program of bolts that have shown issues, the report says; currently there is no standard industrywide program to inspect bolts that have failed or are being replaced, such as after the five-year inspection required for BOPs.

BSEE could proactively work with the oil and gas industry to construct a comprehensive road map of key objectives and priorities to be implemented by the industry, the report says. Industry should have a large role in determining the priority for addressing potential improvements.

The road map could include sections on:

  • investigating bolting cluster failures using a large-scale, fully instrumented test rig that simulates undersea conditions on fasteners;

  • researching and developing innovations that could significantly advance the reliability of offshore fasteners in critical service;

  • identifying gaps in current standards and obtaining the necessary data to guide updates to the standards; and

  • promoting a strategic vision for the safety culture throughout the oil and gas industry. This would include collecting and disseminating information about fastener performance, failures, and near misses, and using this information to guide roadmap priorities.

The report also recommends several other actions the oil and gas industry should take to improve the reliability of undersea bolts. For example, industry should establish a standard laboratory test method to assess how susceptible bolting materials are to cracking and embrittlement from exposure to hydrogen. It should review the standards, such as those related to bolt tensioning, in order to minimize the likelihood of excessive stress being placed on bolts in subsea environments. And it should promote an enhanced safety culture across organizations and disciplines - one that is reflected in work rules and encourages all levels of the organization to improve the reliability of undersea bolts.

The study was sponsored by the Bureau of Safety and Environmental Enforcement of the U.S. Department of the Interior. The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. For more information, visit A committee roster follows.



Riya V. Anandwala, Media Relations Officer
Andrew Robinson, Media Relations Assistant
Office of News and Public Information
202-334-2138; e-mail

Copies of High-Performance Bolting Technology for Offshore Oil and Natural Gas Operations are available from the National Academies Press on the Internet at or by calling 202-334-3313 or 1-800-624-6242. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).


Division on Engineering and Physical Sciences National Materials and Manufacturing Board

Committee on Connector Reliability for Offshore Oil and Natural Gas Operations

Robert E. Schafrik* (chair)
Presidential Distinguished Professor of Industrial, Systems and Manufacturing Engineering
College of Engineering
University of Texas

Robert Pohanka (vice chair)
Director (retired)
National Nanotechnology Coordination Office
National Nanotechnology Initiative
Alexandria, Va.

Clyde L. Briant*
Otis E. Randall University Professor of Engineering
Brown University
Providence, R.I.

Willard C. Capdevielle
President and Founder
Bill Capdevielle Enterprises LLC
Cypress, Texas

Homero Castaneda
Associate Professor and Director
National Corrosion and Materials Reliability Center
Texas A&M University
College Station

Nancy J. Cooke
Professor of Cognitive Science and Engineering
Polytechnic School, and
Science Director
Cognitive Engineering Research Institute
Arizona State University

Thomas W. Eagar*
Professor of Materials Engineering and Engineering Systems
Department of Materials Science and Engineering
Massachusetts Institute of Technology

L. Brun Hilbert Jr.
Principal Engineer
Exponent Inc.
Menlo Park, Calif.

Derek J. Horton
Materials Research Engineer
U.S. Navy Research Laboratory
Alexandria, Va.

David W. Johnson Jr.*
Senior Advisor
Stevens Institute of Technology, and
Journal of the American Ceramic Society
Bedminster, N.J.

David K. Matlock*
University Emeritus Professor
George S. Ansell Department of Metallurgical and Materials Engineering
Colorado School of Mines

Jyotirmoy Mazumder*
Robert H. Lurie Professor of Mechanical Engineering
Department of Mechanical Engineering
University of Michigan
Ann Arbor

Roger L. McCarthy*
McCarthy Engineering
alo Alto, Calif.

John R. Scully
Interim Department Chair, and
Charles Henderson Chaired Professor of Materials Science and Engineering, and
Center for Electrochemical Science and Engineering
University of Virginia

Pol D. Spanos*
Lewis B. Ryon Professor of Mechanical Engineering and of Civil Engineering
George R. Brown School of Engineering
Rice University

Neil G. Thompson
Senior Vice President
Det Norske Veritas (DNV-GL)
Arlington, Va.


Erik B. Svedberg
Staff Officer

*Member, National Academy of Engineering

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