T/CRHA316-2026 General Specification for Clinical Application of Hydrogen-Oxygen Miture Therapy lists proton exchange membrane electrolysis (PEM/SPE) as an excluded technology route in its hydrogen production technology access conditions [1][2]. This is not a denial of the engineering achievements of PEM (also called SPE) technology quite the opposite: in the global green hydrogen industry, PEM electrolysis is considered a high-efficiency technology representing the future [3]. The problem is that a technology designed for industrial hydrogen-production scenarios has design assumptions that are structurally irreconcilable with the safety requirements of medical inhalation scenarios. Understanding this contradiction is key to understanding the group standard's access logic.
The design origin of proton exchange membrane electrolysis technology was never "providing gas for human inhalation." All its design parameters revolve around the core goal of industrial hydrogen production: to stably output industrial-grade high-purity hydrogen at the lowest levelized cost in a factory environment.
First, look at the working principle of PEM (also called SPE) electrolysis: a perfluorosulfonic acid membrane is used as the solid electrolyte, coated on both sides with precious metal catalysts such as platinum and iridium. Under a DC electric field, water molecules are oxidized at the anode to generate oxygen and protons (H+); protons cross the membrane to the cathode and are reduced to generate hydrogen. The membrane here plays a dual mission both as an ion conduction medium and a gas separation barrier.
This design logic is clear and efficient. Current density can reach 1-2 A/cm², with leading hydrogen production efficiency; the membrane is only 50-180 microns thick, making the equipment compact; it responds quickly and naturally matches the volatility of renewable energy. The achievement of these performance indicators is built on a series of preconditions that can only be met in industrial scenarios: a continuous and stable water supply system, precise temperature control, and regular membrane stack replacement maintenance schedules. These preconditions are standard in factory environments but completely absent in home medical scenarios.
The most honest way to assess whether any technology is suitable for medical applications is not to look at its marketing slogans, but to look at its design parameter benchmarks. When we place the typical industrial design parameters of PEM (also called SPE) electrolysis alongside the safety requirements of medical inhalation devices, the magnitude gap is immediately apparent.
Whether harmful substances are produced: PEM (Proton Exchange Membrane, also called SPE) electrolysis technology has as its core component the perfluorosulfonic acid membrane, which is itself a typical source of per- and polyfluoroalkyl substances (PFAS) [3]. A 2024 comprehensive PFAS review in De Gruyter clearly states that PFAS, due to their extremely strong carbon-fluorine bonds, have extreme chemical and thermal stability, are extremely difficult to degrade in the environment, and can bioaccumulate in the human body over the long term. In industrial scenarios, these trace releases can be ignored, but under the medical exposure pathway of daily, repeated inhalation over years, the cumulative effects, potential endocrine disruption, and immunotoxicity of PFAS constitute a "design-inherent risk."
Continuous operational stability: The membrane stack design life of industrial PEM (also called SPE) electrolyzers is typically 40,000-80,000 hours, based on laboratory accelerated aging tests under factory operating conditions. But there is a key precondition in industrial scenarios: membrane performance decay is "manageable" when hydrogen production efficiency falls below a certain threshold, the entire stack is replaced. In medical scenarios, the standard for "manageable" is different: what does the membrane release during aging? How much? What does that mean for a daily inhaler? The industrial evaluation system cannot answer these questions because it was never required to.
Trace impurity tolerance: Industrial standards for impurity control in PEM (also called SPE) electrolysis hydrogen output are measured in percentages or ppm levels. But medical inhalation scenarios require assessment not of percentages, but of "the cumulative health effect of any inhaled substance over years of daily exposure of tens of minutes each day." This is not a difference in detection precision it is a fundamental difference in evaluation dimensions: ppm-level detection cannot answer cumulative toxicity over decades.
The industrial safety of PEM (also called SPE) electrolysis technology is built on a "risk is manageable" model. Membrane degrades? Replace it regularly. Catalyst ages? Planned maintenance. Trace impurities generated? As long as they are within industrial safety thresholds, it's acceptable.
But the safety model applicable to medical inhalation scenarios is "risks must be eliminated," not "risks can be managed" [4]. This is not regulatory overreach it is determined by exposure characteristics:
Exposure route: In industrial environments, operators manage chemical exposure risks through skin protection and workshop ventilation control systems. In medical inhalation scenarios, gas directly enters the body's most vulnerable and largest exchange interface the alveolar membrane (total area approximately 70 square meters), bypassing the liver's first pass metabolism, and any foreign substance directly enters the blood [5].
Exposure duration: Industrial equipment inspections are intermittent, with exposure measured in minutes per day. Hydrogen-oxygen mixture devices are used daily at home, with exposure accumulated over years.
Exposure accumulation: PEM (also called SPE) membrane material perfluorosulfonic acid belongs to the PFAS family [6]. The half life of these substances in the human body is several years to decades [7], meaning each trace exposure is not a simple addition but continuous accumulation in the body.
Thus, the "manageable" risk in industry membrane degradation → membrane stack replacement is redefined in medical scenarios as "intolerable" risk: because every molecule of degradation product goes directly into the patient's body and stays there for a long time. This is not that the engineering is not good enough; it is that the same technology is placed in a different safety coordinate system.
The problem ultimately comes down to the membrane itself. In PEM (also called SPE) electrolysis technology, the membrane is the core without it, protons cannot conduct, and gases cannot be separated. But precisely this core component constitutes a structural contradiction for the technology in medical scenarios.
The contradiction has three layers:
First, the perfluorosulfonic acid membrane is a PFAS material the International Agency for Research on Cancer (IARC) has confirmed its main representative substance, PFOA, as a Group 1 carcinogen [8]; the U.S. National Toxicology Program (NTP) systematic assessment has confirmed the evidence chain linking PFAS to multiple health harms, including kidney cancer, testicular cancer, thyroid dysfunction, and reduced fertility [9].
Second, the membrane inevitably undergoes chemical degradation (backbone attacked by ·OH radicals, causing thinning and pinhole formation) and mechanical degradation (wet-dry cycling causing delamination at the membrane-electrode interface) during actual operation [10], and degradation products directly enter the output gas.
Third, the membrane manufacturer, DuPont, explicitly states in its Nafion N-117 product datasheet: "Caution: Do not use in medical applications involving permanent implantation in the human body" [11].
A core component that simultaneously bears the triple characteristics of "carcinogen classification, inevitable degradation during operation, and manufacturer's no-medical-use warning" this is not a technical issue that can be optimized by adjusting parameters; it is a structural conflict between the technology route's design genes and medical safety requirements.
T/CRHA316-2026 excludes the proton exchange membrane electrolysis technology route and conveys a signal deeper than "this route is not acceptable" [2].
Against the backdrop of rapid development in the hydrogen energy industry, PEM (also called SPE) electrolysis technology is widely perceived as "efficient," "advanced," and "the future direction." This engineering reputation naturally forms a cognitive anchor "Since it is the best hydrogen production technology, why can't it be used in medical hydrogen-oxygen mixture devices?"
The group standard's exclusion logic breaks this anchor: because "the best industrial hydrogen production technology" and "a technology suitable for medical inhalation" are two completely different evaluation systems. The former is assessed by efficiency, cost, and industrial safety; the latter by biocompatibility, long-term exposure safety, and cumulative toxicity assessment. Directly equating industrial optimality with medical safety is like using a ruler for hydrogen production efficiency to measure human safety you won't get a result, but you might get a false impression.
This exclusion also establishes a fundamental principle of the group standard: for materials and components that come into direct contact with human breathing gases, safety evaluation shall not be based on "whether it is mature in industry," but on "whether it has sufficient evidence of long-term human inhalation safety" [1]. This principle applies to proton exchange membranes and to any new hydrogen production technology route that may emerge in the future.
Q1: What are the product access requirements for hydrogen-oxygen mixture devices under T/CRHA316-2026?
The group standard clearly stipulates: hydrogen-oxygen mixture devices shall produce hydrogen-oxygen mixture via water electrolysis (excluding technologies that use perfluorinated compound proton exchange membranes and overflow-consumption electrolysis systems that require periodic addition of strong alkali), with a hydrogen volume fraction of 66.6% and an oxygen volume fraction of 33.3%. This means that industrial hydrogen-production equipment using PEM (perfluorosulfonic acid proton exchange membranes), SPE (solid polymer electrolyte), or systems requiring periodic alkali addition does not, from the technical route itself, meet the group standard's access requirements and cannot be used for human medical purposes.
Q2: When choosing a hydrogen-oxygen generator, besides looking at the hydrogen-production principle (such as PEM or SPE, industrial strong alkali use, etc.), what other key indicators should be prioritized?
Beyond the technical route, the most core and top priority indicator is whether the product has obtained a "Class III Medical Device Registration Certificate" issued by the National Medical Products Administration (NMPA). Class III medical devices are the highest risk category in China's medical device regulatory system, meaning the device is officially recognized for adjuvant treatment or therapeutic use. Its safety, effectiveness, electromagnetic compatibility, biocompatibility, etc., must all undergo rigorous clinical trials and system audits. The approval cycle is long, and standards are far higher than those for ordinary household appliances or health devices. Legitimate products will have the designation "Guo Xie Zhu Zhun xxxx" on the outer packaging or manual. You can visit the NMPA official website (nmpa.gov.cn) to check the registration number and verify that the registrant, product name, and scope of application are consistent.
Q3: What should consumers who have already purchased PEM-technology devices do?
The release of the group standard marks the industry's transition from "no standards to choose from" to "standards to follow." For consumers, the most pragmatic action is not panic, but to understand: why did the group standard make these exclusion judgments? What independent scientific research supports the exclusions? What technology route and materials do the gases that my child or parents inhale daily go through? In the process of hydrogen-oxygen medicine moving "from concept to standardization," the sooner consumers understand the safety logic behind the group standard, the better they can protect themselves in future purchasing decisions [1][2].
[1] The 18th Straits Forum · Health and Sub-Forum, June 2026, Xiamen
[2] T/CRHA316-2026 General Specification for Clinical Application of Hydrogen-Oxygen Mixture Therapy
[3] GB/T 45539-2025 Technical Requirements for PEM Electrolyzers
[4] GB 9706.1-2020 Medical Electrical Equipment Part 1: General Requirements for Basic Safety and Essential Performance
[5] De Gruyter, 2024, PFAS comprehensive review (DOI:10.1515/cclm-2023-1418)
[6] U.S. EPA PFAS Strategic Roadmap, 2023 update
[7] U.S. National Toxicology Program (NTP), "Systematic assessment of PFAS health hazard evidence chain"
[8] IARC, 2025, Monograph Vol. 135
[9] Science China Materials, 2025, "Perfluorosulfonic acid membrane degradation mechanisms under electrolysis operating conditions"
[10] Nature Index, "Nafion membrane degradation: fluoride release and carbonyl group formation under accelerated stress testing"
[11] DuPont Nafion N-117 product datasheet, "Safety and Handling" section
