U.S. Department of Labor t www.osha.gov t (800) 321-OSHA (6742)

Evaluation and Control of Hazards 

from Preservative Coatings during 

Hot Work on Vessels

The construction and repair of vessels often involve the use of hot work processes that can pose serious 

hazards to workers. The presence of flammable or toxic preservative coatings creates serious hazards 

during hot work. The primary hazards include fire, explosion, and inhalation hazards, including gases, 

vapors, and aerosols that can result in damage to workers’ neurological, reproductive or developmental, 

and respiratory systems. Employers must take the necessary precautions before and during hot work to 

reduce worker exposures to toxic substances and protect them from fire and explosion hazards.

Use of Preservative Coatings

Advances in technology have resulted in the elimination of 

preservative coatings containing lead, chromium, cadmium, zinc, or 

polychlorinated biphenyls (PCBs). However, despite the existence of 

safer alternatives, the potential for worker exposure to compounds 

at dangerous concentrations still exists. Applying heat to 

preservative coatings used on vessels, such as paint, can release 

gases, vapors, and aerosols that are flammable and harmful to 

workers. Exposures above OSHA’s permissible exposure limit (PEL) 

may result from hot work being performed on surfaces containing 

preservative coatings, as well as during their removal. OSHA’s 

Safety and Health Injury Prevention Sheets (SHIPS) on Hot Work

and Surface Preparation and Preservation provide more in-depth 

discussion of potential overexposures and risks of fire or explosion 

associated with hot work and preservative coatings. 

Employers must assess the workplace and associated operations to 

determine whether hazards are present, or likely to be present that 

require the use of personal protective equipment (PPE). Whenever 

possible, engineering controls (e.g., elimination or substitution), safe 

work practices, and administrative controls should be used to abate 

hazards before the use of PPE is implemented. 

Hot Work Evaluation of Preservative Coatings

The following safety measures must be taken where preservative 

coatings are present before starting hot work: 

• Evaluate work areas to identify potential hazards, including 

the atmospheric testing to ensure there are no concentrations 

of flammable vapors 10 percent or greater than the lower 

explosive limit. 

• Sample and test preservative coatings with unknown 

flammability to determine if hot work can be safely performed. 

Preservative coatings must be considered to be highly 

flammable when scrapings burn with extreme rapidity.

• Remove highly flammable hardened preservative coatings from 

the location of intended heat application to prevent ignition. 

Verify that the method used for removing the flammable 

coating, such as chemical removers, will not cause a reaction, 

leading to fire or explosion. 

• Strip toxic preservative coatings at least four inches on all sides 

surrounding the area of intended heat application, or provide 

workers with air line respirators in enclosed and confined 

spaces. Air purifying respirators must be worn by workers in 

open air operations during hot work on surfaces coated with 

toxic preservatives. Ensure filters, cartridges, or canisters used 

are appropriate for the specific air contaminant of exposure. 

Shipyard

Employment Fact Sheet
U.S. Department of Labor t www.osha.gov t (800) 321-OSHA (6742)

Toxicity Evaluation of Preservative Coatings

A toxic substance is defined as any chemical substance that has 

yielded evidence of an acute or chronic health hazard, or is the 

subject of a safety data sheet indicating that the material may 

pose a hazard to human health (see 29 CFR 1910.1020(c)(13)). 

OSHA standards outline potentially harmful substances and their 

corresponding PELs in Table Z of 20 CFR 1915.1000. Additional 

guidance may be found at the Permissible Exposure Limits – 

Annotated Tables. To better protect workers, OSHA recommends 

that employers follow the most protective occupational exposure 

limits. The sampling of such coatings and evaluation of the 

results by a competent person is necessary to make an accurate 

determination of the hazards present and associated strategy for 

ensuring worker protection. When evaluating test results, competent 

persons must determine whether further testing by a Certified Marine 

Chemist (CMC) or Certified Industrial Hygienist (CIH) is necessary.

Techniques for Preventing Exposures to 

Toxic Substances

Employers should use a systematic method for evaluating preservative 

coatings and implementing controls to protect workers from exposure 

to gases, vapors, or aerosols that can be released at harmful levels 

during removal and heating. Whenever possible, shipyard employers 

should explore whether an alternative method to hot work, such as 

cold work, is available. Where no such alternatives exist and coatings 

have been determined to be toxic, as prescribed in 29 CFR 1915.53(d), 

at least four inches on all sides surrounding the area of intended heat 

application must be removed in enclosed and confined spaces before 

hot work can be performed, unless workers are supplied with air line 

respirators. In open air, air purifying respirators are required. 

However, the prescribed four inches is only a minimum distance, which 

is dependent on the expected temperature of the heat process and 

the surface area that the flame, arc, or other source of heat contacts. 

Therefore, the evaluation must take into account not only the immediate 

area where hot work is being performed, but the surrounding areas 

(e.g., adjacent locations and the reverse side of the material) as well. 

If surrounding surfaces are covered with a toxic preservative coating 

and have the potential to release harmful gases, vapors, or aerosols 

when heated, the coating must be removed or workers provided with 

the necessary respiratory protection. Where it is difficult to visually 

ascertain the edge of the area of heat application, the area can be 

marked with a 500°F temperature-indicating crayon (or temp-stick). 

If the crayon melts, it indicates insufficient coating removal. An 

infrared device is another alternative that can be used to measure 

surface temperatures. Additionally, as noted at 29 CFR 1915.53(e)

(2), artificial cooling equipment can be used to cool the metal 

surrounding a heated area to limit the amount of preservative coating 

that must be removed. While this particular provision specifically 

addresses hot work performed in enclosed spaces on metals covered 

by soft and greasy preservatives, such cooling equipment is also 

suitable where there is the potential for preservative coatings on 

surrounding areas (e.g., backside of a bulkhead) to smolder or burn.

Use the Process Flow Chart for assistance in determining the steps 

and OSHA standards for safely dealing with preservative coatings 

where heat processes are necessary.

Additional Resources:

• OSHA Shipyard Employment eTool

• National Institute for Occupational Safety and 

Health (NIOSH) Registry of Toxic Effects of Chemical 

Substances (RTECS) 

• NIOSH Pocket Guide to Chemical Hazards

• OSHA Maritime Resource Webpage

For More Information

Your nearest OSHA office can provide more information. Also, 

OSHA’s On-Site Consultation Program offers no-cost and confidential 

occupational safety and health services to small and medium-sized 

businesses in all states, with priority given to high-hazard worksites. 

On-Site consultation services are separate from enforcement 

and do not result in penalties or citations. For more information 

or to find the local On-Site Consultation office in your state, visit 

www.osha.gov/consultation, or call 1-800-321-OSHA (6742).

Workers’ Rights 

Workers have the right to: 

• Working conditions that do not pose a risk of serious harm.

• Receive information and training (in a language and 

vocabulary the worker understands) about workplace 

hazards, methods to prevent them, and the OSHA 

standards that apply to their workplace.

• Review records of work-related injuries and illnesses.

• File a complaint asking OSHA to inspect their workplace if they 

believe there is a serious hazard or that their employer is not 

following OSHA’s rules. OSHA will keep all identities confidential.

• Exercise their rights under the law without retaliation, including 

reporting an injury or raising health and safety concerns with 

their employer or OSHA. If a worker has been retaliated against 

for using their rights, they must file a complaint with OSHA as 

soon as possible, but no later than 30 days. 

For additional information, see OSHA’s Workers page

(www.osha.gov/workers).

How to Contact OSHA 

Under the Occupational Safety and Health Act of 1970, 

employers are responsible for providing safe and healthful 

workplaces for their employees. OSHA’s role is to help 

ensure these conditions for America’s workers by setting and 

enforcing standards, and providing training, education and 

assistance. For more information, visit www.osha.gov or call 

OSHA at 1-800-321-OSHA (6742), TTY 1-877-889-5627.
U.S. Department of Labor t www.osha.gov t (800) 321-OSHA (6742)

This is one in a series of informational fact sheets highlighting OSHA programs, policies or standards. It does not impose any new compliance 

requirements. For a comprehensive list of compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal 

Regulations. This information will be made available to sensory-impaired individuals upon request. The voice phone is (202) 693-1999; 

teletypewriter (TTY) number: 1-877-889-5627.

DSG FS-4169 01/2022

Process Flow Chart: Evaluation and Control of Preservative Coatings during Hot Work

No

Yes

Does the coating contain toxic or hazardous substances?

(1915.53(d))

Yes

Can work be done without removing the coating?

(1915.53)

Yes

Does a preservative coating exist 

where a heat process is to take place?

(1915.53)

No

Is there previous sampling 

data that can be evaluated

for same coating and work 

process within the last year?

(1915.53(b))

No

Yes No

Yes

Host employer (or designee) 

informs all employers, including 

contractors and vendors, of on the 

hazards, safety rules, and 

emergency procedures concerning 

those spaces and atmospheres.

(1915.12(f); 1915.88(e)(3))

Employer (or designee) develops and implements 

appropriate controls for worker protection based on 

the following:

• Makeup of the preservative coating (e.g., lead);

• Job classification (e.g. coating removal, hot work 

personnel, fire watch); and 

• Work processes (e.g., needle gunning, grinding, 

welding).

Employers must train each employee that enters a 

confined space to perform their assigned duties 

safely. Where the use of respirators is necessary, an 

employer respiratory protection program is required 

that entails worksite-specific procedures and elements 

for respirator use.

(1915.9; 1915.12(d); 1915.51; 1915.53; 1915.152; 1915.154)

Can an alternative method 

(e.g., cold work) be used for 

removing the coating?

(1915.13; 1915.33; 1915.34)

Proceed with work/process 

and appropriate controls. 

(1915.51)

Employer (or designee) develops and 

implements appropriate controls before 

proceeding with work/process.

(1915.13; 1915.32; 1915.33; 1915.36)

Yes

Does the alternative method involve 

chemicals that pose toxic hazards?

(1915.33)

No

Proceed with 

work/process 

(1915.13; 1915.34) 

Cold Work Process

Competent person or 

CMC/CIH inspects worksite 

and conducts necessary tests:

• Collects sample of preservative coating

• Evaluates of lab results

A competent person may determine that 

further testing by a CMC/CIH is necessary.

(1915.7; 1915.12; 1915.53(b))

Employer (or designee) ensures a visual 

inspection and atmospheric testing is performed 

before the start of work, and as often as necessary 

during work to maintain safe conditions.

Where metals are covered by soft and greasy 

preservatives, atmospheric testing must be 

conducted immediately after hot work and at 

frequent intervals thereafter to ensure no flammable 

vapors exist.

(1915.12; 1915.15; 1915.53)

No