# A case of lung injury due to a hydrogen explosion caused by the simultaneous use of two home folk remedies devices.
> 家庭用機器2台の同時使用による水素爆発で肺損傷に至った1例


## Abstract

This case report documents, from an emergency-medicine standpoint, a hydrogen explosion that occurred while two home devices were used at the same time and resulted in lung injury. When ignition and explosion occur in an environment where a hydrogen-generating/inhalation device is in use, the harm is not confined to the device: it can extend via the inhalation route to a pulmonary contusion centred on the alveoli (combustion-type lung injury). Combining multiple devices created an unanticipated ignition condition, and serious trauma occurred even in the home environment. The case clinically corroborates the danger of operating devices whose output concentration is far above the empirically validated safe value for the inhalation environment.

### Mechanism

Under hydrogen's very low minimum ignition energy, combined device use produced an unanticipated ignition source and mixing condition; combustion within the inhalation route reached alveolar-level injury.

## Bibliographic

- **Authors**: Tsuchikane M, Yamagiwa T, Takada T, Wakai S, Inokuchi S
- **Journal**: Acute Med Surg
- **Year**: 2024
- **PMID**: [39634382](https://pubmed.ncbi.nlm.nih.gov/39634382/)
- **DOI**: [10.1002/ams2.70019](https://doi.org/10.1002/ams2.70019)
- **PMC**: [PMC11614747](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11614747/)
- **Study type**: human case report
- **Delivery route**: inhalation
- **Effect reported**: adverse

## Delivery context

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

## Safety notes

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [LFL / UFL terminology](https://h2-papers.org/en/safety-notes/lfl-ufl-explained)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 39634382. https://h2-papers.org/en/papers/39634382
> **Source**: PubMed PMID [39634382](https://pubmed.ncbi.nlm.nih.gov/39634382/)