100 years after the creation of NFPA’s standard for gas hazards on vessels, marine safety issues remain as critical as ever
BY GUY COLONNA
In the summer of 1973, I took part in a training program while I was a cadet at the US Coast Guard Academy. The program included several weeks assigned to the marine safety office in San Francisco, where Coast Guard staff performed various maritime safety duties including what is referred to as marine inspection. I didn’t realize it at the time, but the inspections applied an NFPA standard, NFPA 306, Standard for the Control of Gas Hazards on Vessels. It was a standard that would one day become an important focus of my career.
The Coast Guard, which is responsible for commercial vessel safety, conducts inspections of various classes of marine vessels to ensure compliance with federal regulations developed and enforced by the agency. Prior to each inspection, an NFPA-certified professional known as a marine chemist was required to enter and visually evaluate cargo spaces, engine rooms, and void spaces where entry and hot work repairs such as welding were planned to ensure that the confined spaces were safe for entry and that hot work hazards were addressed. Marine chemists used NFPA 306 to help them document any issues and to complete a permit allowing entry and hot work.
In 1986, I arrived at NFPA to oversee the certification program for marine chemists and to serve as the staff liaison to the Committee on Gas Hazards, which was responsible for NFPA 306. I received a crash course in the program’s global significance, since there were NFPA-certified marine chemists serving the maritime industry in ports around the world. Marine chemists served Canadian ports, and today Transport Canada manages a program for its marine chemists, similar to NFPA’s, who also follow NFPA 306. I visited shipyards in Brazil and learned that NFPA 306 was included in that country’s shipyard safety requirements, and I accompanied the port chemist in Singapore during shipyard inspections. The United Kingdom required that a competent analyst inspect and certify vessels for entry and hot work, and both Portugal and Italy had marine chemists.
As a result of the global nature of the maritime community, NFPA and the Marine Chemist Association have shared the best practices represented by the NFPA program whenever those opportunities have arisen. The Panama Canal Commission (PCC) requested NFPA assistance in 1998 as it prepared for the canal’s transfer to Panama in 2000. The PCC proposed a model for its shipyard safety program (there is a shipyard on the canal near Panama City) based on NFPA 306 and marine chemists. Safety professionals employed by PCC applied and trained for certification as NFPA marine chemists with the assistance of the Marine Chemist Association during the early 2000s.
In 2022, NFPA 306 will observe its 100th anniversary, and the standard, along with the role of the marine chemist, have never been more important. Events around the world continue to bear that out. In August 2020, a series of explosions and fires in the port of Beirut—the result of unregulated hot work that started a fire that ignited poorly managed hazardous materials—caused more than 200 deaths and 6,000 injuries and produced an estimated $15 billion in property damage. In February, a fire and subsequent explosion rocked a shipyard on the Indonesian island of Borneo, killing three workers. No cause has been confirmed.
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The standard and its companion marine chemist program grew from a need identified by stakeholders seeking a consistent set of practices that addressed and managed hazards and ensured safety when executed by a skilled professional. The current edition of the standard, as well as the qualifications and practice of marine chemists, reflect an array of industry changes over the years, and the program continues to demonstrate a unique partnership between government and industry that safeguards workers and the workplace. Since the late 1980s, NFPA has provided training for all sectors of the industry—tank ship, barge and towing, offshore, shipyards, Navy and Coast Guard—informing them of the role of regulations, standards, and the marine chemist to promote safe behaviors and invest in a culture of safety. Sound safety management practice for confined space entry and hot work benefits from a program and standard that embrace hazard recognition, evaluation, and control, and that’s been the role of the marine chemist and NFPA 306 for a century and counting.
The seeds of NFPA 306
In the early 1920s, as the nation resumed its business following the end of World War I, the maritime industry found itself facing troubling losses. Cargo vessels, converted to carry troops and supplies in support of the war effort, returned to shipyards for reconversion back to their intended uses as bulk liquid carriers and dry-cargo transportation. Repairs often involved extensive hot work—welding, cutting, and burning—and fires and explosions were common due to inadequate or incomplete preparations necessary to safeguard the hazards posed by the liquid fuels (bunker oils and diesel) and the aggressive hot work. By 1922, the maritime community, including vessel owners, shipyards, marine insurers, marine surveyors, and the petroleum industry, had recognized that something needed to be done to protect its assets.
NFPA had just marked its 25th year in existence, but it was already known for its ability to provide an arena for stakeholders in need of a standard of practice. That’s why representatives of the maritime industry, including members of the American Bureau of Shipping (ABS), approached NFPA in 1922 seeking its assistance with the development of a new safety standard. NFPA accepted the challenge.
Those inquiries resulted in a pair of outcomes: a new standard to safely govern hot work repairs on marine vessels, particularly where cargo or fuel tanks and piping were involved, and the designation of a new specialist whose training and experience allowed them to apply the standard consistently and effectively within the shipyards. The new standard was developed, with industry collaboration, by the NFPA Committee on Marine Fire Hazards, in cooperation with the NFPA Committee on Flammable Liquids. Originally titled “Freeing Oil Tanks, Bunkers, and Compartments of Dangerous Concentration of Flammable, Explosive, or Toxic Gases Previous to Entering for Any Purpose or Making Repairs on Oil Burning or Oil Tank Vessel,” the standard was included as Appendix A in the “Regulations Governing Marine Fire Hazards.” Updates occurred over the next two decades, and in 1947 a completely revised standard was prepared and issued as NFPA 306 by NFPA and a joint committee of the ABS.
An excerpt from the early standard illustrates the range of practices it covered: “Tanks shall be cleaned or steamed, then ventilated, then inspected and tested by the certified competent chemist, whose ability and reliability shall be attested to by the ABS. Where the workspaces also involve adjacent spaces, no repair work permitted until those spaces have also been treated by cleaning, steaming, and ventilating to meet gas free condition. If the oil or sediment has not been completely removed, the certified chemist must advise the repairer at the time of delivery of the gas free certificate of any further cleaning and testing that is required during the actual work. Use of wind sails or forced or induced draft ventilation is required while work is in progress to ensure conditions do not change. Note that the entrant is tied to a rope being managed by two strong men. If entry is required prior to completing the gas freeing process, entrants required to wear gas masks.”
Much of the entry and hot work repair safe practices found in NFPA 306 today can be traced to Appendix A, with the initial steps focusing on the identification of hazards. That includes the atmospheric hazards associated with entry into tanks, holds, and void spaces, as well as the fire and explosion hazards linked to the ignitable liquids present in the cargoes or in fuels and their residues. Next comes hazard evaluation, whereby the known atmospheric hazards and ignitability hazards are monitored qualitatively and quantitatively to determine their presence and severity. Once the hazards have been identified and evaluated, control measures are applied: removing the fuels through cleaning, steaming, and ventilating; periodic retesting of the atmosphere during the work; ventilating the space during the work; and documenting safe conditions on a permit, also referred to as a gas free certificate. The current edition of NFPA 306 also outlines the type or class of vessels required to be inspected by a marine chemist prior to entry or hot work repair and describes the methods by which a vessel is “gas freed.” Much like Appendix A, a vessel owner or repairer can clean the tanks or render them inert, then present the vessel for inspection, testing, and approval by the marine chemist in the form of issuing a permit.

An aerial view taken on August 7, 2020, shows a partial view of the port of Beirut, a damaged grain silo, and the crater caused by the colossal explosion three days earlier of a huge pile of ammonium nitrate that had languished for years in a port warehouse, leaving scores of people dead or injured and causing devastation in the Lebanese capital. GETTY IMAGES
Over the years, as the nature of the hazards grew in complexity, a more complete understanding of the toxic hazards associated with chemical and petroleum cargoes and fuels was established. This made it necessary for spaces to be tested for oxygen content, flammability, and toxicity. The standard also evolved to define specific quantitative criteria for entry and hot work and integrated those levels into standard safety designations. Today, those designations are recognized throughout the industry and within the federal regulatory structure overseen by the Occupational Safety and Health Administration (OSHA) and the US Coast Guard. Both agencies maintain safety regulations that require a marine chemist to certify that safe conditions exist before work can be performed. These kinds of relationships, paired with the need for a standard that is adopted, enforced, and maintained alongside an evolving industry, ensure that the maritime industry benefits from the tenets of the NFPA Fire and Life Safety Ecosystem™.
The rise of marine chemists
In 1922, great foresight was required to realize the nature of the hazards encountered during ship construction and repair, and to create a role for a specialist who could carry out the detailed actions essential to safeguarding not only the workers but the vessels and the shipyards. That first year, ABS certified 25 marine chemists to direct and apply the requirements of a new standard of practice.
The original marine chemists, by and large, worked as laboratory chemists within petroleum refineries, which meant they typically possessed a thorough understanding of the properties and characteristics of the fuels and cargoes. ABS served as the certifying body of the marine chemists until 1963, when NFPA assumed those duties. Under NFPA, more rigor was applied to certification program qualifications, including the creation of a marine chemist qualification board (MCQB) to oversee the admission of applicants, evaluate and recommend approval of those satisfying the requirements for certification, and manage recertification. The qualifications were documented in a set of rules for certification and recertification, which the qualification board directs today. The MCQB consists of representatives from the same stakeholder groups that first approached NFPA a century ago, plus representatives from the Coast Guard, OSHA, and the Navy. The MCQB is appointed by the NFPA Board of Directors, which also approves the rules for certification and recertification and hears appeals on decisions rendered by the MCQB. The marine chemist and NFPA 306 are part of the vessel repair practices observed by the Navy and the Coast Guard, highlighting the value of their participation in the standards development process and certification board.
Today, a marine chemist is a professional who is trained in environmental and occupational safety and health and who is responsible for ensuring that repair and construction of marine vessels can be made in safety whenever those repairs might result in fire, explosion, or exposure to toxic vapors or chemicals. Marine chemist qualifications include a bachelor’s degree plus specific course work in chemistry; maritime industry work experience, such as a shipyard or as a shipyard contractor, service as a licensed merchant mariner, or Navy or Coast Guard service; laboratory work experience; completion of field experience gained through work with certificated marine chemists; and completion of training modules. Once admitted as a marine chemist trainee, the MCQB monitors progress with each of the steps until the trainee applies to meet with the MCQB for the certification examination. Certification requires marine chemists to complete a medical examination, attesting to, among other things, the physical ability to enter and work within confined spaces; written examination on NFPA 306, OSHA, and Coast Guard regulations, and practical elements required of a marine chemist; and an in-person interview with the MCQB. Marine chemists must complete recertification every five years, a process that requires written examination and review of their performance by the MCQB.

Modern marine chemists work outside the confines of a laboratory, often inspecting ships as well as overseeing maintenance and repairs on vessels. GETTY IMAGES
Each year, NFPA certificated marine chemists issue more than 30,000 certificates documenting safe conditions for entry and hot work involving all types of vessels and myriad hazards. A typical certificate might address the safe conditions for an average of 10 spaces, which means that marine chemists ensure the safety of over 300,000 specific work sites annually. The scope of a marine chemist’s work can span a liquid-carrying barge, a chemical tank ship, an offshore drilling vessel or drill rig, a tow boat, or a liquid natural gas carrier. Changes in the industry continuously prompt changes to NFPA 306, and the standard provides a forum for any proposed changes designed to preserve or improve safety. Marine chemists occasionally perform inspections and tests for entry and work on aboveground petroleum storage tanks, relying on the same ability to recognize, evaluate, and control similar hazards in non-marine environments. Their broad qualifications make them an asset whenever hazards associated with confined spaces and hot work repairs must be addressed on marine vessels and within shipyards, marine terminals, and waterfront facilities.
NFPA 306: next steps
In my 40-plus years in and around the maritime industry, I have observed significant changes as industry segments have expanded and contracted due to a variety of factors. A recent example is the growth of liquefied natural gas (LNG) as both a cargo and a fuel. NFPA 306 acknowledged the unique construction of LNG tankers by incorporating a special chapter within the standard, and marine chemists inspecting those vessels must complete additional training to earn a special endorsement to their certification. With the increase in LNG exports from US ports, marine chemist inspection of tankers required by the Coast Guard increased, so NFPA, MCQB, and the Marine Chemist Association ensured that additional training was provided to meet the industry need. LNG is also being used to fuel marine vessels, including container ships and cruise ships, adding another specific need for inspections, which the standard addressed with revisions to the current edition. LNG will likely be an area considered in future editions of NFPA 306.
It’s fitting that the standard begins the revision process for its 2024 edition just as it begins its second century. The First Draft phase for standards development kicks off at the end of 2021 with an agenda of proposed changes that includes inspection of aboveground storage tanks located at waterfront facilities, since the hazards and safeguards associated with entry and work on these storage vessels (such as water tanks and diesel tanks) are the same as for a maritime vessel. The revision process will also consider shipbreaking facilities. As vessels age out of service, these facilities become important means for tearing down vessels to scrap metal. The scope of NFPA 306 applies to shipbreaking, which involves considerable hot work and poses a persistent hazard. Shipbreaking operations within the US have typically been an on-again, off-again enterprise, but their recent resumption has prompted a closer look at the guidelines contained in the standard. The agenda for the upcoming revision cycle includes proposed changes that would strengthen the controls required before shipbreaking could proceed.
NFPA 306 and the marine chemists have demonstrated an ability to adapt, which remains critical to the continued success in protecting workers and work sites. Industry stakeholders have observed firsthand that when the standard is followed and a marine chemist affirms that safe conditions exist with inspection and documentation on a certificate, major incidents rarely occur. To maintain this level of protection, marine chemists must continue to apply updated editions of the standard going forward to assure the safety of workers and shipyards into the next century.
Guy R. Colonna, PE, is a former senior principal engineer and division director at NFPA. He is currently principal engineer at FSL Consulting, LLC, an industrial safety consulting company in Brooklin, Maine. Top photograph: Getty Images