National institutions must lead by example regarding the publication of official documents

The original COMEX-based NORMAM-15/DPC saturation procedures, which were adopted and published in Portuguese and English by the Brazilian Navy Directorate of Ports and Coasts in June 2011, are an evolution of the previously published COMEX MT-92 procedures that are still in force in the French regulations. They have been later on published and reinforced in 2019 in the CCO Ltd Diving Management Study #5 “Implement Normam-15/DPC saturation diving procedures” that rigorously conforms to this first 2011 edition, except that the gas values for the descent and the storage periods that were missing in the official document have been provided by Jean-Pierre Imbert, who worked as the COMEX company diving manager at the time and who can be considered the lead author of many COMEX procedures. The reasons for the reinforcements were that several improvements to diving procedures have been adopted in the industry since the creation and official publication of this table in 2011, necessitating the incorporation of these updates to keep this CCO Ltd study current. Therefore, some complementary procedures from the latest NORSOK standards U-100, the Diving Medical Advisory Committee (DMAC), the International Marine Contractors Association (IMCA), the UK Health and Safety Executive (HSE), and the French Ministry of Labour are included in this study, along with conclusions from relevant research such as the paper “A review of accelerated decompression from heliox saturation in commercial diving emergencies” by Jean-Pierre Imbert, Jean-Yves Massimelli, Ajit Kulkarni, Lyubisa Matity, and Philip Bryson. Incorporating these procedures into the original COMEX-based ones results in a safe, cost-free alternative to recent saturation methods, enabling operations at depths up to 350 m. This approach has been favorably received by several scientists and companies, as it is cited in multiple scientific studies and frequently downloaded. We can therefore consider that, currently, the only more modern procedures are those based on the sliding windows concept invented by Jean- Pierre Imbert. However, these tables are available only privately and are not freely accessible to the public. It is also worth noting that two updates published by Brazilian authorities were not considered, as these documents were only available in Portuguese, and many in the scientific community, including the lead author of these procedures, were unaware of them. In 2023, the Brazilian authorities superseded the NORMAM-15/DPC procedures with the NORMAM-222/DPC procedures, published both in Portuguese and English. That has resulted in the need to compare these new guidelines with those previously published in 2011 to evaluate the evolution of these saturation diving procedures and, consequently, determine whether they still conform to the original COMEX procedure, whether additional reinforcements have been introduced to comply with the latest safety practices, and whether changes have been made that cause them to no longer conform to the original decompression model.

Comparison method A point-by-point comparison method was used to ensure no details were missed. Thus, this involved writing the procedure steps into two columns: one for Normam 15/DPC-2011 and one for Normam- 222/DPC. These steps were arranged side by side for easy comparison, with chapters and sections separated by sufficient space to avoid confusion. As previously mentioned, Normam-222 saturation procedures were compared only with those of the 2011 version of Normam-15, as the "Study #5 CCO Ltd", published in 2019, is built on them and does not incorporate the previously mentioned updates from the Brazilian authorities. This comparison, available in the CCO Ltd Diving Management Study #13, "Gap analysis between the Normam-15/DPC- 2011 and Normam-222/DPC Saturation Diving Procedures", showed some differences, so we have contacted the Brazilian authorities for clarification, and they have kindly responded. Their answers have been introduced in the sections of this gap analysis that raised questions.

Results The first point to note is that the English version should not be considered valid, as essential elements such as the calculation method for stabilization periods between the surface and 100 m have been omitted. This omission results in the formula for exposures between 100 and 180 m being applied to both types of exposures, contrary to the Portuguese version, which faithfully follows the original procedure on this point. In addition, translations are not always precise. This resulted in the use of the Portuguese version, which was translated using the “DeepL” software, as well as the artificial intelligence programs “Mistral” and “ChatGPT” when necessary. Nevertheless, for convenience, the texts from the English version were used when they were compliant. The cover of this English-translated version mentions that it is not considered an original legal document. However, why publish documents that are not verified to conform to the original? We suppose there are sufficiently talented translators in Brazil who could have done this work properly. To answer our remark regarding this incorrect edition, the Brazilian authorities said that this item will be adjusted in a future revision.

To conclude Some may argue that what we propose is an unattainable ideal and that maintaining the status quo is the only realistic option. On the contrary, we believe that continuing along the current path risks the collapse of the system initially designed to regulate and support professional practices. Such a collapse could lead to a world governed not by fairness and merit, but by a handful of influential organizations competing to impose their economic models, often relying on clientelism-based practices. In such a world, professional organizations, companies, and individuals would lose their rights and autonomy. Progress would depend not on competence or innovation, but on securing the political favor of dominant institutions. This scenario is the antithesis of the "democratic world" so often promised by politicians. To contribute to designing the "ideal diving world", we hold that the principle of "every person to their trade", also known as "deference to expertise", must be the rule. Therefore, states, supranational, and international organizations must adopt transparent, science-based, and consistent standard-setting practices. These practices should be open to analysis, discussion, and, when necessary, criticism by professional bodies and individuals. To truly earn their legitimacy, national institutions must lead by example. There is no other path forward.

Discussion We must first emphasize that, as demonstrated in the CCO Ltd Diving Management Study #5, it would have been possible to reinforce the initial procedure, and thus avoid entering a process of validating a new decompression procedure, by adding safety practices currently in use in the diving industry without altering the key elements of the decompression procedure, which include: 1. The compression rate to the “storage depth”, stabilization stops, and stabilization periods before diving, which are calculated to manage phenomena such as compression arthralgia, narcosis, and High Pressure Nervous Syndrome (HPNS). 2. The maximum descent and ascent rates from and to the bell 3. The maximum excursion distances and the excursion rules associated with these distances. 4. The published diving profile rules (for example, the “V” profile NORSOK). 5. The final decompression process. 6. The recommended proportions of gas for each phase. Regarding the previously mentioned lack of scientific documentation, it must be remembered that, since antiquity, it has been common practice for scientists to publish the conclusions of their work to the scientific community before releasing them to the public. This practice, which aims to ensure that the described study is scientifically accurate, has also allowed us to refer to these works and use them for further research. Scientists involved in creating diving decompression procedures are accustomed to working this way. For example, the latest explanations of the current evolution of the US Navy tables are presented in the documents “Testing of Revised Unlimited Duration Upward Excursions During Helium-Oxygen Saturations Dives” published by Dr. Thalmann in 1990, “VVal-79 Maximum Permissible Tissue Tension Table for Thalmann Algorithm Support of Air Diving” published by Doctors Wane Gerth and David Doolette in 2012, and “Manned Validation of a US Navy Diving Manual, Revision 7, VVal-79 Schedule for Short Bottom Time, Deep Air Decompression Diving” published by Doctors Brian Andrew and David Doolette in 2020. The studies that resulted in the creation of the Normam-15/DPC-2021 are described in a document titled “Deep diving: The Comex experience”, which has been written and published by Jean Pierre Imbert at the Bergen conference in September 2005. More recently, Dr. Risberg, the lead author of the editorial team of the Norwegian diving and decompression tables (NDDT), has published a document entitled "NDDT—Probability of Decompression Sickness", which details the conceptual process undertaken by the team to create these decompression tables. Some may argue that the gas values mentioned in the Normam- 222/DPC have been in force in Brazilian waters since 2016 and that no decompression incidents have been publicly reported, so this modified procedure can be considered safe. However, this argument is fallacious for the following reasons: • First, there is no data to verify this point accurately, considering that many events may have gone unreported by companies and the divers experiencing them. • Second, even if no visible decompression sickness incidents have been reported, it does not mean that divers have not suffered from undetected decompression sickness or various stresses related to decompression that could lead to medical complications later. For example, in a document titled "Saturation Diving: Physiology and Pathophysiology," Alf O. Brubakk, John A.S. Ross, and Stephen R. Thom state that while testing the US Navy's "Unlimited Excursion" tables from 300 to 250 meters of seawater (msw), results showed that all divers had significant amounts of vascular gas bubbles in the carotid artery, the blood vessel supplying the brain. However, none of the divers exhibited acute clinical symptoms. This phenomenon was confirmed during upward excursions from 300 to 250 msw in an experimental saturation dive, where Dr. Brubakk et al. found arterial bubbles in the carotid arteries of all six participants, without resulting in clinical cases of neurological decompression sickness. However, post-dive examinations revealed a minor cerebral lesion in the diver with the highest number of carotid bubbles. Therefore, we can consider that the naked eye and feeling are not sufficient to detect some accidents and that only tools such as doppler, echocardiography, bioimpedance, urine testing, salivary testing, blood testing, magnetic resonance imaging (MRI), etc., allow specialists to detect the effects of such not visually detectable decompression accidents. The recent studies “Commercial Divers’ Subjective Evaluation of Saturation”, “Vascular Function Recovery Following Saturation Diving”, and “Hydration Status during Commercial Saturation Diving Measured by Bioimpedance and Urine Specific Gravity”, available in our database, are examples of the use of such tools to identify the various stresses and not visible decompression problems in relation to saturation diving. To the best of our knowledge, there has not been any study based on such research protocols that concludes that changing the initial PPO2 of a COMEX-based saturation procedure to US Navy PPO2 values does not affect divers. Based on the above and the elements mentioned in the previous section, it is evident to us that the Brazilian authorities made several undocumented and inconsistent modifications to key points, resulting in the creation of a new decompression procedure with some critical parts lacking scientific evidence. In addition to the problem above, which results in the procedures Normam-222/DPC no longer being compliant with the original ones published in 2011, we must consider that numerous elements are missing for an extended period of time, which demonstrates issues regarding document control procedures and an obvious lack of reactivity to address them. Consequently, we have considered that these procedures cannot be viewed as relevant for the operations for which they were created, and that the only procedures to be implemented remain the NORMAM-15/DPC-2011, faithfully described in the CCO Ltd diving management study #5, except in Brazilian waters, where the authorities may impose their unsuitable modifications. Therefore, while the adoption of the initial saturation procedures by the Brazilian authorities in 2011 could be seen as an example to follow by national bodies, the modifications they implemented since 2016 and the lack of reactivity they demonstrate to correct issues should be regarded as an example not to follow, which opens to discussion regarding the duties of states regarding the publication and implementation of standards. For an accurate discussion, it is essential to remember that in an "ideal world," governments are expected to establish standards based on scientific research, which they either fund or adopt, in line with their role as judges and arbitrators, ensuring that the procedures applied within their territory adequately protect all citizens. These standards are then adopted by companies and professional organizations, which use them to develop their guidelines, and can be shared with other national and international organizations. Most governments are also engaged in the application of the World Medical Association’s “Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects”. This declaration, first published in 1964 to prevent unethical medical practices and amended in 1975, 1983, 1989, 1996, 2000, 2008, 2013, and 2024, is composed of 37 articles classified into topics, among which the following refer to procedures to implement when undertaking new studies involving human participants: • Article 12, in the section “General Principle”, states that medical research involving human participants must be conducted only by individuals with the appropriate ethics and scientific education, training, and qualifications, in addition to the fact that such research requires the supervision of a competent and appropriately qualified physician or other researcher. It also states that scientific integrity is essential in medical research involving human participants and that involved individuals, teams, and organizations must never engage in research misconduct. • Article 17 in the section “Risks, Burdens, and Benefits” says that all medical research involving human participants must be preceded by careful assessment of predictable risks and burdens to the individuals and groups involved in the study in comparison with foreseeable benefits to them and other individuals or groups affected by the condition under investigation. Also, measures to minimise the risks must be implemented, and the risks and burdens must be continuously monitored, assessed, and documented by the researcher. • Article 18, also in the section above, states that physicians and other researchers may not engage in research involving human participants unless they are confident that the risks and burdens have been adequately assessed and can be satisfactorily managed. In addition, when the risks and burdens outweigh the potential benefits or there is conclusive proof of definitive outcomes, physicians and other researchers must assess whether to continue, modify, or immediately stop the research. • Article 21 in the section “Scientific Requirements and Research Protocols” mentions that medical research involving human participants must have a scientifically sound and rigorous design and execution that is likely to produce reliable, valid, and valuable knowledge and avoid research waste. It also states that research must conform to generally accepted scientific principles and be based on a thorough knowledge of the scientific literature and other relevant sources of information. • Article 22, which follows Article 21 in the abovementioned section, states that the design and performance of each research study involving human participants must be clearly described and justified in a research protocol. This protocol should include a statement of the ethical considerations involved and indicate how the principles in the Declaration have been addressed. Additionally, it should provide information regarding aims, methods, anticipated benefits, potential risks and burdens, qualifications of the researcher, sources of funding, any potential conflicts of interest, provisions to protect privacy and confidentiality, incentives for participants, provisions for treating and/or compensating participants who are harmed as a result of participation, and any other relevant aspects of the research. • Article 23 in the section “Research Ethics Committees” mentions that the protocol must be sent for review, comments, guidance, and approval to a relevant research ethics committee before starting the research. That this committee operates transparently and maintains independence from outside influences, in addition to having enough resources. Its members must be well-educated, trained, qualified, and diverse to assess the research effectively, suggest changes, and eventually withdraw approval and suspend ongoing studies. Finally, this article concludes that no protocol changes can occur without committee approval. • Article 26 in the section “Free and Informed Consent” states that each potential participant must be adequately informed in plain language of the aims, methods, anticipated benefits, possible risks and burdens, qualifications of the researcher, sources of funding, potential conflicts of interest, provisions to protect privacy and confidentiality, incentives for participants, provisions for treating and/or compensating participants harmed as a consequence of participation, and any other relevant aspects of the research. The potential participant must be informed of the right to refuse to participate in the research or withdraw consent to participate without reprisal. Special attention should be given to the specific information and communication needs of individual potential participants and the methods used to deliver the information. These articles are reused by competent international bodies such as the “Council for International Organizations of Medical Sciences (CIOMS)” and UNESCO and are reproduced in the Brazilian Ministry of Health's "Operational Manual for Research Ethics Committees (Manual Operacional para Comitês de Ética em Pesquisa)". So they should be applied in Brazil when research is undertaken to issue a new decompression procedure. Given the absence of any documentation substantiating the implementation of these articles, it can be deduced that they have likely not been applied for the study of these Normam-222/DPC saturation decompression procedures and the previous 2016 and 2021 revisions. This is likely due to a lack of awareness among the individuals who imposed these US Navy procedures and probably believed their actions were optimal. It is worth noting that, although the Brazilian government is highlighted here, we must recall that it is not the sole entity to publish documents with inconsistencies made by civil servants who lack sufficient knowledge to fully understand what they write. For example, we can note that in Section 9 of Chapter 3, “Procedures et Moyens de Decompression”, of the “Arrete du 14 mai 2019 relatif aux travaux hyperbares effectues en milieu subaquatique—mention A (Decree of May 14, 2019, relating to hyperbaric work carried out underwater—reference A)”, it is stated that a diver who has been involved in an inshore or inland saturation dive should wait 12 hours before being authorized to be transferred by plane with the cabin pressure at 250 hectopascals (long-range flight), but that if this diver had undertaken the same saturation with the same work offshore, the standby time before flying the same distance becomes 48 hours. Therefore, it appears that the individuals who wrote this document did not understand that the standby time before flying is related to decompression. Other inconsistencies can be noted in this document. This means that governments should employ experienced specialists to compile and publish their directives, which must be based on consistent reasoning and scientific evidence. Due to the specific aspects of diving and ROV operations, some issues, such as those related to decompression, may fall outside the competencies of their employees. For this reason, it is common for competently managed national organizations to appoint independent bodies to compensate for this lack of expertise. For example, from the 1960s to the late 1990s, the French government commissioned COMEX to develop its mandatory diving tables and related standards and conduct research on diving physiology, which culminated in the Hydra 10 dive (reaching 701 meters) in 1992 (As mentioned above, it is unfortunately no longer the case). It has also been the case in the United Kingdom, where the Health and Safety Executive (HSE) appointed organizations such as "Unimed Scientific Limited" to undertake physiological research and provide documented guidelines on diving procedures. It is still the case with the Norwegian government that appoints the "Norwegian Underwater Institute" (NUI) for similar tasks, or the Polish government that interacts with the "Polish Hyperbaric Medicine and Technology Society", or the United States administrations, such as OSHA (Occupational Safety and Health Administration) and NOAA (National Oceanic and Atmospheric Administration), that refer to the diving procedures published by the US Navy. These appointed organizations are distinguished by their ability to provide documentation that adequately describes and supports the standards they have issued, and to give the names of their authors. This is, for example, the case of Dr. Valerie Flook, who is known to have signed numerous UK-HSE documents and, more recently, those published by NUI, the Polish Hyperbaric Medicine and Technology Society, or the US Navy (see in our database). Contrary to these examples, we are witnessing a phenomenon where some states create mandatory standards solely based on guidelines from various professional organizations they adopt without prior study or consultation with competent experts, often relying only on unverified assumptions. It is true that, due to their small size and limited budgets, some of these states lack adequate resources and expertise regarding underwater operations. However, nothing prevents them from occasionally engaging advisors who could assist in selecting existing standards and guidelines suitable for the norms they aim to establish. We are therefore faced with a scenario opposite to the ideal, which raises questions about the validity of the standards these states create, adopt, publish, and approve. Let's be clear: The problem does not lie with the professional organizations that publish guidelines to defend their viewpoints and achieve a certain harmony regarding the procedures applied by their members, as they are entirely within their role by doing so. The issue stems from the inability of some states to make appropriate decisions for ensuring the reliability of the information they provide, which typically falls under their responsibilities, due to the problems mentioned above. This often leads to illogical national standards that may then be taken as references, encouraging the spread of other inadequate procedures whose authors cannot justify the reasons behind them. As these improperly founded norms accumulate erratically, they can also become circular references, leading to a monoculture that lacks adequate questioning of the validity of the promoted procedures. This creates a chaotic situation where national bodies, which should serve as references, lose their prerogatives to pressure groups, as previously explained in the article "About Standards," published in this section of the website in January 2023. It is worth noting that this lack of scientific and technical supporting documents is not only a fact of only these governments, as we can also highlight that some well-known supranational organizations, such as the International Maritime Organization (IMO), the International Organization for Standardization (ISO), the European Standards, and others commonly referenced, are known to issue standards for which we cannot see the scientific and technical studies used or who compiled them (except for ISO regarding this last point), which contrasts with the virtuous behaviour we advocate, and some organizations and states mentioned above have demonstrated that it can be implemented. Such a chaotic situation should not continue, or the foundation on which safety procedures rely will vanish, potentially leading to accidents due to a loss of fundamental knowledge and people applying rules without understanding their basis. Therefore, we advocate for national, supranational, and international organizations to be exemplary in how they present their standards, which should be thoroughly documented and validated by the scientific and professional communities. Remember that scientific references are now easily accessible, as many free databases are available to the public, making it easy to provide them. Of course, implementing such practices may be challenging for some personnel who have worked for some time in organizations accustomed to imposing rules without explanation or discussion. It is therefore the responsibility of the hyperbaric workers' community to strongly request that the standards imposed on them are based on recognized scientific studies, cited in published documents, and endorsed by competent scientists and the communities involved with these norms. In other words, we can agree that those who issue national and international standards should enforce them only if they can explain the reasons for the norm they want to publish, on what these new norms will be beneficial for the community, on which scientific studies these norms are based, whether these studies have achieved consensus regarding their conclusions, and whether the norm will not conflict with existing ones. Additionally, the names of the people involved in the elaboration of standards should be mentioned, as is customary in the scientific community. Therefore, if these elements are not adequately provided, the new standard should not be implemented.

The second point is that this evaluation revealed that while most parts of the saturation procedures remain unchanged, and some improvements, such as the respect of the biological cycle of the divers, have been provided, the Brazilian authorities made the following modifications, resulting in these procedures no longer being compliant with the original ones published in 2011: • The initial PPO2 values during the decompression phase, initially between 0.48 and 0.5 bar, have been reduced to 0.44 and 0.48 ATA. These absolute atmosphere (ATA) values are those used by the US Navy revision 7 (published in 2016) for the storage and ascent phases. Taking into consideration that a scientist would have used pascals or, alternatively, millibars, given that the table is written in metric units, we have concluded that this modification has not been performed by a scientist or a diving specialist accustomed to decompression procedures. Additionally, recent procedures designed by Jean Pierre Imbert for reputed companies that are IMCA members show that the value of 480-500 mb has been maintained with equivalent storage PPO2 values to those he initially provided for the NORMAM-15/DPC-2011. Furthermore, studies such as the paper "Evaluation of North Sea saturation procedures through divers monitoring" show that these tables yield very satisfactory results regarding oxygen and decompression stresses. Therefore, the question can be raised about the safety performances that can be expected from new decompression procedures that continue to use the former rates of ascent but with lower chamber PO2. To further explain this point, it must be taken into account that the decompression strategies of COMEX-based tables and US Navy tables are not the same: While COMEX-based procedures such as the Normam-15/DPC-2011 use slow, continuous, and uninterrupted ascent rates (1.2 msw/hr from 350 to 20 m and 0.67 msw/hr from 20 m to the surface) with a PPO2 of 480 to 500 mbar after an at- depth rest period in the living chamber (commonly called "storage") with a PPO2 of 380 to 450 mbar, the US Navy procedures use faster ascent rates interrupted by 8 hours of stops per 24 hours divided into at least two parts, with a PPO2 between 0.44 and 0.48 ATA (445.83 mb - 486.36 mb) and the same PPO2 during the "storage" period. We can note that these standby times (stops) during the ascent compensate for the faster ascent rates compared to the COMEX procedures (see the comparison of both decompression curves below). Therefore, taking into account that the decompression strategies are different, we can consider that changing the PPO2 of the NORMAM- 15/DPC by adopting those of the US Navy resulted in creating a new decompression procedure that should have been rigorously tested.

As a conclusion, it seems to us that no modification of these original gas values was necessary and that this modification has been imposed without the support of any published scientific study and without consulting the lead author of the original procedure or members of the scientific community, which the Brazilian authorities implicitly confirmed in a message received on 07 August 2025, as they did not provide any documented answers to our questions regarding this critical point.

• The percentage of O2 during the final phase of decompression is now limited to 21% instead of the initial 25%. While the 25% limit may increase the risk of fire if an imprudent operator exceeds it, it offers a comfortable operating range for the Life Support Technicians (LST), which is significantly reduced with a limit to only 21%. Considering that the LST on duty will require a certain degree of flexibility, we made the remark that the 23% value recommended by IMCA, previously retained in the initial edition of the CCO Ltd study #5, is balanced and appropriate. The Brazilian authorities responded that the final part of the text was incorrectly edited and should have stated that the ideal oxygen percentage must remain within the range of 19% to 23%, with 21% as the recommended value. Therefore, a correction is to be made to this already 9-year- old text. • Note that the PPO2 values for the compression and storage phases that were lost in the initial official 2011 document, despite being provided by the author in the initial COMEX procedure, are still missing in the NORMAM-222/DPC revision. The Brazilian authorities did not comment on our remark regarding this point. • The excursion combination #7 “Exceptional upward excursion followed by a standard upward excursion” has disappeared in the document NORMAM-222/DPC. The Brazilian authorities said that it was due to an editorial oversight at the time of publication, which had not been formally identified until now.

Christian CADIEUX & Doctor Jean Yves MASSIMELLI