Boat Manufacturing

Based on 2018 data, North Carolina has 38 businesses listed in NAICS 336612 (boat manufacturing)*.

* Reference USA

Boat Manufacturing

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Most boats are built and repaired using fiberglass reinforced plastics. Reinforced plastics or fiberglass reinforced plastics refers to a composite consisting of a polymer matrix and fiber reinforcement.

The simplest and most popular production methods employ an open mold in which the hull and other large parts are built in a three-step process that involves spraying a mixture of styrene monomer and polyester resin with catalyst and accelerator to facilitate the hardening (curing) process. Catalysts are added to the styrene monomer - polyester resin mixture shortly before use to initiate the polymerization necessary between the polyester resin, which contains reactive chemical sites, and the styrene monomer. The catalyst molecule does not become part of the final structure; it just activates the reaction. The accelerator allows the reaction to proceed at room temperature and/or at a greater rate, but has no effect on the mixture unless a catalyst is added.

In the first step, the mold is sprayed with a layer of gel coat (pigmented polyester resin mixture that hardens). This becomes the smooth outside surface of the part. In the next step, a skin coat of chopped glass fiber and styrene monomer and polyester resin is applied to the hardened gel coat layer. Finally, additional layers of fiberglass cloth and chopped glass fiber saturated with resin are added until the desired thickness is reached. Between applications, each layer of fiberglass and resin is compressed by hand rolling.

Core foam, a two-part foam system that combines spray dried polymeric resin with a foaming catalyst, is installed in the boat for more support. Stiffening, which is the addition of wood components or metal parts, strengthens the bore of the boat and enables other parts to be attached to the hull later during the assembly process.

The last stage of production is to finish the boat or hull. This consists of removing any flash, raised fibers, sharp edges and corners; painting; adding boat trim and preparing for shipping. This involves grinding, sawing, spraying or hand touch up, and drilling and buffing as required to meet the builders’ specifications.


What are the hazards associated with reinforced plastics manufacturing?

Physical hazards associated with boat manufacturing using reinforced plastics are primarily due to fire hazards associated with the use of flammable liquids and organic peroxides (a type of catalyst) in spray applications and cleanup of spray equipment, as well as accumulations of combustible dust generated during the finishing of hulls and other large parts. In addition, workers may be exposed to the risk of electrocution when using electrically powered tools and other equipment that have not been properly maintained and inspected.

Health hazards associated with boat manufacturing using reinforced plastics arise from exposure to styrene monomer and solvents (e.g., methyl ethyl ketone) used in the spray application of styrene monomer and polyester resin onto the boat mold and built up layers. Styrene can cause irritation of the eyes and mucous membranes and can cause gastrointestinal effects. Long term exposure to styrene by inhalation can cause central nervous system effects, such as headaches, fatigue, weakness and depression. Styrene may also damage peripheral nerves and cause changes in the kidneys and blood. Exposure of unprotected skin to the solvents used can cause defatting of the skin resulting in dermatitis.


What can I do to protect myself and others?

Engineering and Work Practice Controls. Conduct spraying applications only in well ventilated areas designed and designated for that purpose. When using electrically powered tools for work outside of spray areas, do not use tools and cords where the cord insulation is not intact or where the ground pin has been removed from the plug. Catalysts and accelerators must be stored separately and no mixing may take place in the chemical storage area.

Personal Protective Equipment. When engineering controls are not adequate to maintain airborne exposures below permissible exposure limits (PELs) or, in the absence of applicable PELs, recommended exposure limits, appropriate respiratory protection must be used in conjunction with an effective respiratory protection program. This may be especially necessary when spraying styrene monomer-polyester resin with catalyst in areas of large hulls with decreased ventilation or later when conducting interior spraying after the deck has been lowered in place. In addition, appropriate skin protection, especially chemical resistant gloves, should be worn when spray applying the resin-catalyst mixture and smoothing out the fiberglass mats into the resin mixture.

What resources are available to assist employers?

Training and Outreach Services

Presentations on a variety of topics associated with boat building and reinforced plastics are available to assist employers in training their staff. These include: hazard communicationrespiratory protection, and personal protective equipment. Each of these presentations should be modified to address site-specific conditions and hazards. 

In addition, the education, training and technical assistance bureau provides free online safety and health training and outreach services (i.e., speaker's bureau requests, safety booths) upon request. 

Lastly, the NCDOL Library offers free safety and health videos (including streaming video services) and related research assistance on consensus standards (i.e., ANSI, NFPA, NEC).

Safety and Health Programs

Example safety and health programs are available are available for employers to download and adapt to their specific conditions. Safety and health programs relative to boat building and reinforced plastics manufacturing include: hazard communication program; personal protective equipment program; and respiratory protection program.

A-Z Safety and Health Topics

More information related to boat building and reinforced plastics can be found on the A-Z topics pages for flammable liquids, hazard communication, personal protective equipment (PPE), respiratory protection and styrene

Consultation Services

The consultative services bureau provides free and confidential onsite consultation regarding worksite safety and health hazards.


Which standards apply?

OSH has adopted the following standards which are applicable to boat manufacturing in North Carolina. Note: Please also check the standards information and activity webpage to see if there has been any recent or upcoming regulatory activity on this topic. 

General Industry

Other Applicable Standards

The Which OSHA Standards Apply webpage can also help identify other standards that may be applicable to your worksite.


Where can I learn more?

Industry Guides

Technical Assistance

If you would like to receive interpretive guidance on this or any other OSH standard or topic, you can submit your questions using the Ask OSH web form, by e-mail to or by calling 919-707-7876.