Category Archives: Pipeline

‘Tis the Season…for Safe Digging

By Chair Jennifer Homendy

The warmer months are here, which means more time outside for many of us, whether for recreation or to tackle home-improvement projects.

Personally, I’m looking forward to running in the mornings, biking in the evenings, and spending weekends digging around in my vegetable garden — but not before taking an important safety action.

Call 811 Before You Dig

April is National Safe Digging Month, the perfect time to remind you to call 811 a few days before you put a shovel in the ground for any reason. This includes:

  • Planting trees, bushes, flowers, or vegetables.
  • Installing a fence or a mailbox.
  • Building a deck.

Calling 811 will direct you to the appropriate resource in your state, where you can request to have the location of buried utilities marked with paint or flags before breaking ground. Check out to learn more — some states even have an online portal where you can submit an electronic request.

It doesn’t matter what the project is, how deep you plan to dig, or whether you’ve dug there before. Utility lines and wells can be located just inches below the surface or even change depths over time, which might not be as uncommon as it sounds.

Understanding that things shift under our feet is important, especially when you consider how much is going on beneath the surface: there are 2.8 million miles of regulated pipelines and 17,000 underground natural gas storage wells in the U.S., according to the Pipeline and Hazardous Materials Safety Administration (PHMSA).

Don’t Risk It  

The number-one cause of gas distribution pipeline accidents is excavation damage caused by third parties: anyone not employed by the gas company, such as homeowners or contractors.

In fact, more than a third of all PHMSA-reportable gas distribution pipeline accidents in 2019 had “excavation damage” listed as the incident cause (PHMSA 2021). Of these, 88% were attributed to a third-party.  

If you don’t call 811 before your next home-improvement project, you could disrupt the internet service to your whole neighborhood. Each year, damage to underground utilities costs the U.S. an estimated $30 billion.

Or you could put your entire community at risk. “Improve Pipeline Leak Detection and Mitigation” is on the NTSB’s Most Wanted List because damaged pipelines can be extremely dangerous. 

Unfortunately, this is something I’ve seen up close.

Devastation in San Francisco, California

I was the Board member on scene for the NTSB investigation of a February 6, 2019, pipeline accident in San Francisco, California.

An outdoor fire burns in front of a mini excavator amid smoke as firefighters try to extinguish the flames.
Northwest-facing view of fire during emergency response. (Photo courtesy of PG&E.)

What happened?

In digging to install underground fiber-optic cables, a contractor struck a pipeline, releasing over 1.9 million cubic feet of natural gas. The gas soon ignited.

The fire, which had flames more than two-stories high, reached a fully occupied restaurant with a rental unit above before spreading to the neighboring buildings.

Miraculously, there were no injuries. The accident did, however, cause over $10 million in damage. It also put many lives at risk, including those of the first responders.

How did this happen?

Our investigation determined that the probable cause of the fire was, in laymen’s terms, the contractor’s failure to follow safe digging practices.

While the contractor did call 811 to have utilities marked before beginning work, he used an excavator to mechanically dig too close to the marked utility lines. As a result, the excavator struck the pipeline, which released the gas that later ignited.

The safe thing to do — and the practice required under state law — would have been to use a lower-impact digging technique that close to the pipeline, such as hand digging.

Know What’s Below

While you might not be installing fiber-optic cables in your neighborhood, we can all take a lesson from San Francisco: Call 811 before you dig for any reason — and follow the guidance you’re given. It’s the only way to know what’s below. Never, ever take the risk.

Be careful this spring, wherever your home-improvement projects take you. And if you’re a gardener like me, here’s hoping these April showers pay off with beautiful May flowers…and some home-grown vegetables, too.

Improving Safety in the Second-Largest Continent

By Nicholas Worrell, Chief, NTSB Safety Advocacy Division

In August, 2019, I wrote that Safe Skies for Africa was ending, but that the safety journey would go on in Africa, the world’s second-largest and second-most-populous continent. Earlier this month, it was my pleasure to represent the NTSB in a presentation about best practices in safety advocacy at the Civil Aviation Operational Safety Workshop in Cape Verde.

The occasion was Aviation Safety Week, which gathered together transportation safety leaders from seven African nations, the EU, and the United States to share safety knowledge. Attendees were interested to learn from my presentation that in the United States, the accident investigator—the NTSB—has no power whatsoever to require change.

Enter Advocacy.

It’s been said that information + persuasion = advocacy. The idea is never to misrepresent; rather, it is to present information that makes the case most compellingly. If the case is compelling enough, your advocacy might inspire people to act. Then, they might influence others to act as well, creating a critical force multiplier. I spoke to my audience about advocacy methodology, messaging, and tools, and the absolute need for collaboration, working with and through others. I reminded my audience, though, that advocacy differs with the context and the organization. At the NTSB, for example, it’s the one way we can bring about change and encourage implementation of our recommendations. However, I urged safety leaders in Africa to be mindful that all advocacy is local. What might work in the United States might not necessarily work for all of Africa.

Ultimately, wherever it is done, advocacy done right moves the needle toward saving lives. As transportation safety leaders, I told my audience, we must communicate our work to gain the desired impact and outcomes. We must be proactive and go to our audience, not sit back waiting for them to come to us.

It was an honor addressing these passionate transportation safety leaders from the African region. We should always remember that our transportation safety work crosses air, land, and sea. When we share our lessons learned and best practices, and when others share theirs with us, we may save lives not just nationally, but globally, as well.

The 2021-2022 MWL After One Year: Noticeable Progress But Few Closed Recommendations

By Kathryn Catania, Acting Director, NTSB Office of Safety Recommendations and Communications

Since the unveiling a year ago of the 2021-2022 cycle of the NTSB’s Most Wanted List of Transportation Safety Improvements, we have seen increased awareness and discussion of safety items, high levels of engagement from the public, and incremental progress toward implementation of many recommendations.

In the past year, the NTSB has already successfully closed eight safety recommendations associated with this MWL cycle. But that is not enough. There are 167 other key recommendations that, if implemented, would save lives, and prevent injuries.

Soon after the unveiling of the MWL last year, NTSB Board members and staff sprang into action to educate, engage, and amplify the critical safety messages of our 10 safety improvements. Here’s a quick look by mode, starting with Highway, which makes up 5 of our 10 safety improvements. 


In recent years, we have increasingly expressed our highway safety goals in the language of the Safe System Approach—the very approach that we use in our own safety investigations. (We first discussed the approach in our 2017 report on reducing speeding.)

The Safe System Approach views every aspect of the crash as an opportunity to interrupt the series of events leading to it, and an opportunity to mitigate the harm that the crash does. People make mistakes, but safe roads, safe vehicles, safe road users, safe speeds, and post-crash care can combine to prevent the crash entirely, or failing that, to prevent the deaths or serious injuries of road users.

This paradigm shift applies to each of the highway safety improvements on the MWL, and is mentioned by name in “Protect Vulnerable Road Users Through a Safe System Approach,”

Between May 2021 and February 2022, we produced seven virtual roundtables to explain the approach and call for its adoption.  National and international experts discussed the approach and shared their successes and challenges. More than 1,000 advocates, regulators, academics, and others attended our webinars.

Included in the series hosted by Chair Homendy was a Safe Speeds Roundtable that explored the “Implement a Comprehensive Strategy to Eliminate Speeding-Related Crashes” safety improvement. Additionally, a “Behind the Scene @NTSB” podcast featured discussion on speeding and vulnerable road users.

In 2021, the Department of Transportation and Congress incorporated the approach into the DOT’s National Roadway Safety Strategy and the Infrastructure Investment and Jobs Act, respectively.

Will the new model result in lifesaving protections? Only final, and positive, closure of our recommendations will answer that. But the signs are very good, with the alignment of Congress, the DOT, and the road safety community.

Our MWL safety improvement, “Require Collision-Avoidance and Connected-Vehicle Technologies on all Vehicles,” could result in far superior situational awareness on our roads… if sufficient spectrum is available for the safety improvement.

Vehicle to everything (V2X) technology can save lives but has been delayed, and might be reduced or stopped, due to FCC rulings limiting the spectrum for safety operations. We released a four-part video series in which Member Graham interviewed some of the leading experts in V2X technologies—including academics, researchers, automakers, and policymakers—to discuss what can be done to find a way forward to deployment. 

In progress toward Eliminating Distracted Driving,  Vice Chairman Landsberg and staff joined government officials, industry, academia, insurers, and transportation safety advocates to announce the launch of a new National Distracted Driving Coalition. This is the first such broad national coalition on distracted driving.

We kept working with states considering lowering their BAC limit from .08 to .05 or lower, to help Prevent Alcohol- and Other Drug-Impairment. The National Highway Traffic Safety Administration (NHTSA) has now evaluated the results from Utah, which has made the change to .05. Not surprisingly, the lower threshold prevented drinking and driving and saved lives. NHTSA’s study showed that the state’s fatal crash rate dropped by 19.8% in 2019, the first year under the lower legal limit, and the fatality rate decreased by 18.3%.


To highlight our two aviation MWL safety items, “Require and Verify the Effectiveness of Safety Management Systems in all Revenue Passenger-Carrying Aviation Operations” and “​Install Crash-Resistant Recorders and Establish Flight Data Monitoring Programs,” we met with operators and pilots from the Helicopter Association International, General Aviation Manufacturers Association, and National Business Aviation Association, among others. In webinars, podcasts, and at in-person national conferences, Board members talked with Part 135 and Part 91 operators and pilots to identify challenges. Our outreach meetings alone reached more than 1,500 operators nationwide.


With an increasing number of deadly fishing vessel accidents in recent years, Office of Marine Safety Director Morgan Turrell and Chair Homendy hosted a virtual roundtable on improving fishing vessel safety that was viewed by over 1,000 people. Panelists discussed what can be done to address commercial fishing safety, implement NTSB safety recommendations, and improve the safety of fishing operations in the United States.

Pipeline and Hazardous Materials

Our MWL calls for pipeline and hazardous materials (hazmat) stakeholders to “Improve Pipeline Leak Detection and Mitigation” by equipping all pipeline systems with leak-detection systems and automatic shutoff or remote-control valves. These valves allow for quick detection and mitigation.

Additionally, we produced a video featuring Member Michael Graham and Hazardous Materials Investigator Rachael Gunaratnam, which explores cases in which odorants failed as a natural gas leak-detection strategy, and promotes both required natural gas leak detectors, and voluntary adoption of such detectors until they are required.


To highlight the dangers to rail roadway workers and to help Improve Rail Worker Safety, Member Tom Chapman wrote a blog on rail worker safety, discussing how the railroad regulators—the Federal Railroad Administration (FRA), the Federal Transit Administration (FTA), and the Pipeline and Hazardous Material Safety Administration (PHMSA)— are in the best position to make change.

We also completed our investigation of the April 24, 2018, accident in which an Amtrak rail watchman was killed in Bowie, Maryland. As a result of this investigation, we called on the FRA and Amtrak to put an immediate end to the use of train approach warning (TAW) systems as the sole method of on-track safety in areas covered by positive train control.

To mark the anniversary of the January 2017 train collision in Edgemont, South Dakota, we also issued a media statement again urging railroads to act to better protect rail roadway workers.

Looking ahead

We are pleased by the engagement of so many of our safety advocacy partners, industry groups, and associations in the past year, to promote our recommendations and highlight transportation safety concerns. Also, we acknowledge that many industry groups and operators are making voluntary efforts to improve safety, including on some of our recommendations. However, without mandates, many others may not act.

We remain disappointed by the lack of movement by regulators to implement the safety recommendations associated with our MWL. While there has been some progress during this first year, much more needs to be done to implement the 167 remaining safety recommendations associated with the current list. The longer these authorities wait to implement our recommendations, the greater the risk to the traveling public. Safety delayed is safety denied.

The NTSB will not stand by quietly and watch as regulators, industry, and other recommendation recipients ignore and dismiss our safety recommendations—and neither should the public. As NTSB Chair Homendy expressed in recent remarks to the largest highway safety gathering in the U.S, “The horrific toll of people who’ve died on our roads and their families… millions of people who were injured… are counting on us to “fight like hell” for the next family. To give a voice to those who no longer have one.” 

All our lives are on the line, and no death in transportation is acceptable. It is our mission to advocate for the changes outlined in our safety recommendations which, if implemented, will save lives.

Safety is a shared responsibility. We all play a role in getting us to zero transportation deaths. The NTSB cannot do this alone. We need each of you, individually and collectively, to help us advocate for these critical safety improvements.

A New Year’s Resolution We All Can Make: Prioritize Safety

By Nicholas Worrell, Chief, NTSB Safety Advocacy Division

As 2021 ends, it’s time to reflect on the past 12 months and begin to set goals for the year ahead. After all, as Zig Ziglar once said, “if you aim at nothing, you will hit it every time.” So, let us all aim to improve the safety of our transportation system in 2022.

The NTSB recognizes the need for improvements in all modes of transportation–on the roads, rails, waterways, pipelines, and in the sky. Our 2021–2022 NTSB Most Wanted List of Transportation Safety Improvements (MWL), released in April this year, highlights the transportation safety improvements we believe are needed now to prevent accidents and crashes, reduce injuries, and save lives. We use the list to focus our advocacy efforts and to serve as an important call to action. We ask lawmakers, industry, advocacy, community organizations, and the traveling public to act and champion safety.

As a fellow safety advocate, I ask you to join me in a New Year’s resolution: I pledge to do my part to make transportation safer for all.

To help you take steps to accomplish this resolution, our MWL outlines actions you can take to make transportation safer:

  1. Require and Verify the Effectiveness of Safety Management Systems in all Revenue Passenger-Carrying Aviation Operations
  1. Install Crash-Resistant Recorders and Establish Flight Data Monitoring Programs
  1. Implement a Comprehensive Strategy to Eliminate Speeding-Related Crashes
  1. Protect Vulnerable Road Users through a Safe System Approach 
  1. Prevent Alcohol- and Other Drug-Impaired Driving
  1. Require Collision-Avoidance and Connected-Vehicle Technologies on all Vehicles
  1. Eliminate Distracted Driving
  1. Improve Passenger and Fishing Vessel Safety
  1. Improve Pipeline Leak Detection and Mitigation
  1. Improve Rail Worker Safety

Achieving these improvements is possible; otherwise, they wouldn’t be on our list. The NTSB MWL includes tangible changes and solutions that will, undoubtedly, save lives. But it’s only words on a list if no action is taken. Unlike Times Square on New Year’s Eve, we cannot drop the ball on improvements to transportation safety. The clock is ticking, and the countdown has begun—we can’t afford to waste any more time. Make the resolution to do your part to make transportation safer for all!

In closing, I’d like to thank the transportation safety stakeholders, industry, lawmakers, and advocates we have worked with in 2021 and we look forward to working together in 2022 and beyond.

Improve Pipeline Leak Detection and Mitigation

By Member Michael Graham

Every day more than 2.6 million miles of pipelines across the United States transport enormous volumes of natural gas and liquid petroleum that provide for the nation’s energy needs. These pipelines crisscross the country under our neighborhoods, homes, and businesses. While, statistically, pipelines are the safest method for energy transportation, the NTSB has investigated some accidents that demonstrate the need for improved pipeline leak detection and mitigation:

  • ​On February 23, 2018, a natural gas-fueled explosion at a house in Dallas, Texas, injured all five occupants, one of whom died. The house sustained major structural damage. Investigators located a through-wall crack in the 71-year-old natural gas main that served the residence and positive gas measurements leading from this crack to the residence. Investigators believe the pipeline was likely cracked in 1995 by accidental damage from mechanical excavation equipment. Leaked gas accumulated and eventually ignited from the gas main, which was damaged during a sewer replacement project 23 years earlier. Atmos Energy Corporation failed to detect the leak during an earlier investigation of two related natural gas incidents just two days before the February 23rd explosion.
  • On August 10, 2016, a 14-unit apartment building in Silver Spring, Maryland, partially collapsed due to a natural gas-fueled explosion and fire, which also heavily damaged an adjacent apartment building. Seven residents died and 65 were transported to the hospital, along with three firefighters, who were treated and released. The probable cause was the failure of an indoor mercury service regulator with an unconnected vent line, which allowed natural gas into the meter room where it accumulated and ignited.
  • On September 9, 2010, a 30-inch-diameter segment of an intrastate natural gas transmission pipeline, owned and operated by the Pacific Gas and Electric Company (PG&E), ruptured in a residential area in San Bruno, California. The rupture produced a crater about 72 feet long by 26 feet wide. The section of pipe that ruptured, which was about 28 feet long and weighed about 3,000 pounds, was found 100 feet south of the crater. PG&E estimated that 47.6 million standard cubic feet of natural gas was released, ignited, and resulted in a fire that destroyed 38 homes and damaged 70, killing eight people and injuring many more. Several people were evacuated from the area.

High Consequence Area Leaks

According to the Pipeline and Hazardous Materials Safety Administration (PHMSA), in the last five years, an estimated 1.05 million leaks have been repaired on gas distribution systems. While most pipeline leaks are minor, during the same time, there have been 827 leaks in high-consequence areas – segments of pipeline systems within more populated areas that pose the greatest threat to human life and property – on gas transmission systems, and an estimated 167 accidents on gas distribution and transmission systems.

Leak Detection and Mitigation

Pipelines reliably and efficiently transport the energy that provides heat and electricity for countless Americans. Ensuring the safe distribution and transmission is paramount. Pipeline leak-detection and mitigation tools are essential and can make the difference between a minor leak and a deadly explosion. The NTSB first identified the need for leak-detection and mitigation methods in natural gas transmission and distribution pipelines nearly 50 years ago, but PHMSA, the federal pipeline regulator, has yet to require operators to use these life-saving measures, and many operators have yet to act on their own.

Pipeline systems equipped with leak-detection systems and automatic shutoff valves, or remote‑control valves, can warn operators of an imminent accident and allow for quick mitigation. Also, placing gas service regulators outside buildings can prevent a gas-leak incident; yet, many older homes and multifamily structures still have regulators inside, which can trap accumulating gas and lead to an explosion. And finally, methane detection devices help mitigate the consequences of a natural gas leak by alerting the public, thereby minimizing exposure.

I encourage PHMSA, industry groups, pipeline operators, and the public to work together to ensure the continued safe transportation of our important energy resources.

What is the Solution?

The Role of The Regulator

PHMSA is trusted to act on behalf of citizens to enhance pipeline safety. To better protect public safety, the NTSB has called on PHMSA to:

  • Require all operators of natural-gas transmission and distribution pipelines to equip their supervisory control and data-acquisition systems with tools to help recognize leaks and pinpoint their location.
  • Require automatic shutoff valves or remote-control valves to be installed in high‑consequence areas and in class 3 and 4 locations.
  • Require that all new service regulators be installed outside occupied structures and that existing interior service regulators be relocated whenever the gas service line, meter, or regulator is replaced. Multifamily structures should be prioritized over single-family dwellings.
  • Require methane-detection systems in residential occupancies with gas service.

The Role of Industry Groups

Gas industry groups can also play a critical role in improving public safety. The NTSB urges industry groups to:

  • Revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane-detection systems for all types of residential occupancies with gas service.
  • Develop additional guidance for gas distribution operators so they can safely respond to leaks, fires, explosions, and emergency calls.

Operators Can Enhance Safety Directly

Regardless of when—or if—PHMSA makes the NTSB’s recommended changes, pipeline operators can take steps now to mitigate gas pipeline risks. The NTSB recommends operators take the following action:

  • Review and update, as needed, their incident-reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs.
  • Equip supervisory control and data-acquisition systems with tools to assist in leak detection.
  • Install remote-closure and automatic-shutoff valves in high-consequence areas and class 3 and 4 locations.

These steps taken by the regulator, industry groups, and operators can reduce gas pipeline risks.

What You Can Do

The public also has an important role in preventing pipeline leaks and incidents.

The most common cause of a pipeline leak is accidental damage. If you are planting a tree, installing a fence, or digging on your property for any other reason, call 8-1-1 before you dig. The NTSB has investigated numerous accidents in which accidental damage played a role.

You can also greatly decrease the possibility of an undetected gas buildup by purchasing and properly installing a methane detector in your home. Early detection is critical.

As a reminder, if you ever smell gas, please evacuate the area, and contact 9-1-1 and the gas company.

Improve Pipeline Leak Detection and Mitigation is a safety item highlighted on the 2021-2022 Most Wanted List of Transportation Safety Improvements.

Learn more on

In this video, NTSB Member Michael Graham and HAZMAT Investigator Rachel Gunaratnam, talk about why leak-detection and mitigation tools are essential and can make the difference between a minor incident and a deadly explosion.

Atmos Energy Corporation Natural Gas-Fueled Explosion
Dallas, TX | February 2018

Building Explosion and Fire
Silver Spring, MD | August 2016

Pacific Gas and Electric Company Natural Gas Pipeline Rupture and Fire
San Bruno, CA | September 2010