HYDROGEN SAFETY

The Role of Hydrogen in the Energy Transition

Many experts agree that clean and renewable hydrogen is a viable alternative energy source to help us transition away from fossil fuels, combat climate change, and achieve multi-sectoral decarbonization. Renewable hydrogen has the potential to replace fossil fuels in hard-to-abate sectors, such as heavy-duty trucking, aviation, maritime shipping, agriculture, and industrial processes. 

Figure 1: H2@SCALE DIAGRAM (Source: U.S. Department of Energy, U.S. National Clean Energy Strategy and Roadmap)

Some stakeholders are concerned about hydrogen safety and its leakage potential. While hydrogen is known to have safety hazards, it also has properties that can make it safer than conventional fuels, including gasoline, diesel, natural gas, jet fuel, and uranium, when handled responsibly.

Hydrogen is a safe, non-toxic, and reliable fuel, with 95 million tons of hydrogen produced and consumed each year around the world.

HYDROGEN HAS THE FOLLOWING SAFETY BENEFITS AS A FUEL SOURCE:

Safety features are designed and engineered into hydrogen systems, regulated by governments in accordance with expert third-party international hydrogen safety standards.

Hydrogen is a nontoxic, colorless, odorless, and tasteless gas, which minimizes the risk of contamination in case of leakages or spills.

Hydrogen is much lighter than air (14 times lighter) and about 57 times lighter than gasoline vapor, so it dissipates rapidly when released. This allows for the rapid dispersal of the fuel in the case of a leak.

As hydrogen rises in the surrounding air, it will also not pose a risk of contamination to nearby natural resources.

Hydrogen is not a greenhouse gas, although it can have an indirect influence on warming by impacting atmospheric chemistry. Accordingly, standards for its production, transport, and use are designed to minimize leakage.

Hydrogen rises rapidly in the surrounding air, so it is unlikely to remain near the ground where people would be located in case of fire. Accordingly, the chances of explosion at ground level are much lower than gasoline or propane.

1- Safety features are designed and engineered into hydrogen systems, regulated by governments in accordance with expert third-party international hydrogen safety standards.
2- As hydrogen rises in the surrounding air, it will also not pose a risk of contamination to nearby natural resources.
3- Hydrogen is a nontoxic, colorless, odorless, and tasteless gas, which minimizes the risk of contamination in case of leakages or spills.
4- Hydrogen is not a greenhouse gas, although it can have an indirect influence on warming by impacting atmospheric chemistry. Accordingly, standards for its production, transport, and use are designed to minimize leakage.
5- Hydrogen is much lighter than air (14 times lighter) and about 57 times lighter than gasoline vapor, so it dissipates rapidly when released. This allows for the rapid dispersal of the fuel in the case of a leak.
6- Hydrogen rises rapidly in the surrounding air, so it is unlikely to remain near the ground where people would be located in case of fire. Accordingly, the chances of explosion at ground level are much lower than gasoline or propane.

Commonly Asked Questions

Is hydrogen safe for humans?

Under normal conditions, hydrogen is generally safe for humans. However, like all fuels, hydrogen must be handled responsibly and can behave dangerously under specific conditions.

If hydrogen gas is released in an open environment, it will rise and disperse rapidly. While indoors, the gas would concentrate at the ceiling necessitating proper ventilation requirements. Due to its non-toxic, non-poisonous nature, hydrogen does not pose a risk of contamination to nearby natural resources (groundwater, etc.). It will also not produce fumes nor contribute to significant atmospheric pollution in the long term.

Hydrogen has a significantly wider flammability range (4-74% in air, by volume) compared to gasoline vapor and natural gas. However, at concentrations below 10%, the energy required to ignite hydrogen is high, making hydrogen significantly more difficult to ignite than gasoline vapor or natural gas (See references # 1, # 2, # 3). More technical information on hydrogen safety and precautions can be found on the DOE Hydrogen Safety factsheet here.

What are the side effects of hydrogen exposure?

Like all gases (except for oxygen), hydrogen can cause asphyxiation, producing symptoms such as headaches, dizziness, and nausea. However, due to its lighter-than-air nature and high diffusivity, this is very unlikely in a well-ventilated or open environment. Hydrogen does not directly threaten human health if leaked or released into the environment.

What are the side effects of hydrogen exposure?

Like all gases (except for oxygen), hydrogen can cause asphyxiation (producing symptoms including headaches, dizziness, and nausea), but its diffusivity due to its small molecular size makes this unlikely. Hydrogen does not directly threaten human health if leaked or released into the environment. 

Are hydrogen fuel cell vehicles safe?

Light-duty hydrogen fuel cell electric vehicles are now commercially available in certain markets, including California. Hydrogen fuel cell buses and heavy-duty trucks have been demonstrated, and pilot testing of a variety of heavy-duty hydrogen fuel cell vehicles is underway. Studies have demonstrated that when used in vehicles, hydrogen poses risks of the same order of magnitude as conventional fuels.

In several aspects, hydrogen is actually a safer fuel than gasoline or natural gas. As it has a lower radiant heat when combusted and a higher oxygen requirement for combustion than gasoline, hydrogen is comparatively safer in the event of a car accident due to the reduced risk of secondary fires and explosions. However, like any other fuel, including gasoline and diesel, hydrogen is still susceptible to accident scenarios, including:

1. Fuel tank fire or explosion in unconfined spaces
2. Fuel tank fire or explosion in tunnels
3. Fuel line leaks in unconfined spaces
4. Fuel leak in garages
5. Refueling station accidents

These risks can be mitigated or minimized through safety measures, including leakage preventative system design, pressure relief device vents, protection of high-pressure lines, leakage detection, and ignition prevention measures.

Can hydrogen be transported safely?

Gaseous and liquefied hydrogen is transported safely today by trucks, and gaseous hydrogen is transported safety today via pipeline, including adapted natural gas delivery infrastructure with minor modifications. Approximately 1,600 miles of commercial hydrogen pipelines are in operation within the U.S. Researchers and developers continue to explore potential pathways to enable lower-cost, more reliable, and leak-proof hydrogen distribution, such as fiber-reinforced polymer (FRP) pipelines.

 

Can hydrogen be transported safely?

Gaseous and liquefied hydrogen is transported safely today by trucks, and gaseous hydrogen is transported safety today via pipeline, including adapted natural gas delivery infrastructure with minor modificationsminor modifications. Approximately 1,600 miles of commercial hydrogen pipelines are in operation within the U.S. Researchers and developers continue to explore potential pathways to enable lower-cost, more reliable, and leak-proof hydrogen distribution, such as fiber-reinforced polymer (FRP) pipelines..

Can hydrogen be safely stored?

Hydrogen has been safely stored for a long time. Currently, hydrogen is stored as a compressed gas in high-pressure, reinforced steel or carbon fiber containers either for stationary or on-road transport. Bulk hydrogen is commercially stored today in underground, purpose-built salt dome caverns. Three salt domes in Texas are in commercial operation, supplying refineries and petrochemical plants with feedstock.

A new salt cavern is under construction in Delta, Utah, the Advanced Clean Energy Storage (ACES) site. This cavern will store renewable electricity in the form of hydrogen as long-duration energy storage for later conversion back to electricity.

 

Can hydrogen be safely stored?

Hydrogen has been safely stored for a long time. Currently, hydrogen is stored as a compressed gas in high-pressure, reinforced steel or carbon fiber containers either for stationary or onroad transport. Bulk hydrogen is stored in underground, purpose-built salt dome caverns. Three salt domes in Texas are in commercial operation, supplying refineries and petrochemical plants with feedstock.
A new salt cavern is under construction in Delta, Utah, the Advanced Clean Energy Storage (ACES) site. This cavern will store renewable electricity in the form of hydrogen as long-duration energy storage for later conversion back to electricity.

Safety Standards

What domestic and international standards and regulations exist on hydrogen safety?

Hydrogen safety standards exist for the 95 million tons of hydrogen produced, sold, and transported worldwide today. The Occupational Safety and Health Administration (OSHA) has standards that address worker safety for hydrogen production sites, while the Pipeline and Hazardous Materials Safety Administration regulates pipeline and other delivery methods.

Hydrogen safety standards have been developed with the key goals of:

  1. 1. Improving public safety
  2. 2. Creating interoperability that allows for hydrogen industry growth
  3. 3. Simplify the installation process
  4. 4. Minimizing redundant and/or ineffective regulations
The Safe Hydrogen Project has created a map of hydrogen safety standards for storage, handling, and transportation. Furthermore, the Department of Energy has also developed a Hydrogen and Fuel Cell Codes and Standards Database, which contains relevant codes and standards organized by application type, location, organization, etc.

All fuels and energy carriers pose safety risks if handled improperly. When handled responsibly, renewable hydrogen can be less dangerous than other flammable fuels used in today’s fossil fuel-based economy. However, to accelerate renewable hydrogen’s widespread adoption, industry and government institutions must build on existing robust safety protocols and continue to make safety a key priority for investment and refinement.