Welding on preservative coatings

Before welding, cutting, or heating a surface with an unknown preservative coating, a competent person must test the coating to determine its flammability. See 1926.354(a).

• The standard requires the test be done by a "competent person."
• If you cannot determine flammability by inspection, perform a small, controlled scraping/ignition test under safe conditions and with appropriate controls in place.
• Employers should document that a competent person performed the test as part of their job hazard assessment; for guidance on employer hazard assessments see OSHA's PPE hazard assessment requirements.

A preservative coating is considered "highly flammable" when scrapings from it burn with extreme rapidity. See 1926.354(a).

• If scrapings ignite and burn very quickly during the competent person's test, the coating meets the standard's definition of highly flammable.
• If you observe this behavior, follow the stripping and other precautions required by 1926.354(b).

When a preservative coating is determined to be highly flammable, it must be stripped from the area to be heated to prevent ignition. See 1926.354(b).

• Employers must remove the coating from the specific zone that will be exposed to welding, cutting, or heating.
• In addition to stripping, employers should use standard hot-work controls (e.g., fire watch, fire extinguishers, isolation of combustibles) as part of their overall fire prevention program.

In enclosed spaces, employees must either have the toxic coatings stripped at least 4 inches from the area of heat application or be protected by airline respirators that meet subpart E requirements. See 1926.354(c)(1).

• Option 1: Strip toxic preservative coatings for a minimum of 4 inches from the heated area.
• Option 2: Provide employees with air line (supplied-air) respirators that comply with the construction respiratory protection requirements in subpart E (see 1926).
• Employers must perform a hazard assessment to determine which option is appropriate; see OSHA's letter on PPE hazard assessment requirements.

When working in the open air on surfaces covered with toxic preservative coatings, employees must be protected by a respirator in accordance with the construction requirements of subpart E. See 1926.354(c)(2) and the general 1926 respiratory protection rules.

• The specific respirator selected must be appropriate for the hazard and chosen after a hazard assessment; see OSHA's PPE hazard assessment requirements.
• For hazardous dusts and fumes (including certain preservative chemicals), employers should consult safety data sheets (SDSs) and follow subpart E guidance when selecting respirators.

Preservative coatings must be removed a sufficient distance from the heating area so the temperature of the unstripped metal is not appreciably raised; the distance depends on conditions and may be reduced by artificial cooling. See 1926.354(d).

• There is no fixed numeric distance in the standard; the competent person must determine how much coating removal is necessary based on material thickness, heat input, and other factors.
• Artificial cooling (for example, wetting or mechanical cooling) may be used to limit the cleaned area, but employers must ensure the retained coating and surrounding metal do not reach temperatures that cause ignition or release of toxic fumes.

The testing requirement applies to welding, cutting, or heating — any of those heat-producing operations on surfaces covered by a preservative coating of unknown flammability. See 1926.354(a).

• Employers must ensure a competent person performs the flammability test before any of these hot-work operations begin.

A competent person should perform the flammability test — that is, an individual designated by the employer who is knowledgeable about the test procedure, can identify hazards associated with the coating, and has the authority to take corrective action. See 1926.354(a) and the general 1926 guidance.

• Employers must ensure the competent person has the training and experience to judge flammability and the authority to stop work or require stripping or respiratory protection.
• Documenting who performed the test and the results is a good practice and supports the employer's hazard assessment obligations (see OSHA's PPE hazard assessment requirements).

If scrapings of the coating burn with extreme rapidity during the competent person's test, the coating is "highly flammable" and must be stripped from the area to be heated. See 1926.354(a) and 1926.354(b).

• Observe flame speed and ease of ignition from small test scrapings; rapid, vigorous burning calls for stripping.
• If in doubt, err on the side of stripping or using controls (ventilation, respiratory protection) until hazard is characterized.

Yes; in enclosed spaces, employers may choose to protect employees with airline respirators that meet subpart E instead of stripping the coating, but if they choose not to strip they must provide the required supplied-air respirators. See 1926.354(c)(1).

• The two options are mutually exclusive: either strip at least 4 inches from the heating area or supply airline respirators that meet applicable construction respiratory protection requirements.
• Employers must perform a hazard assessment to justify relying on respirators and must follow the respirator program elements in subpart E (see OSHA's PPE hazard assessment requirements).

Yes; the standard requires that in the open air employees be protected by a respirator in accordance with subpart E when working on surfaces covered with toxic preservatives. See 1926.354(c)(2).

• Employers must select respirators appropriate to the contaminant and exposure level after conducting a hazard assessment (see OSHA's PPE hazard assessment requirements).
• Even outdoors, increased ventilation does not always eliminate the need for respiratory protection when toxic coatings are involved.

No; in enclosed spaces the standard specifically requires airline (supplied-air) respirators as one option — the alternative is stripping at least 4 inches — so a filtering facepiece alone would not satisfy the enclosed-space provision. See 1926.354(c)(1).

• For other situations subpart E governs respirator selection; employers must choose respirators based on the hazard and exposure (see 1926 and OSHA's PPE hazard assessment requirements).
• Some specific contaminants (e.g., asbestos) have stricter respirator rules; see OSHA's LOI on Respirator selection for asbestos work for an example of more stringent requirements in certain standards.

Yes; employers may use artificial cooling of the metal surrounding the heating area to limit the size of the area that must be cleaned. See 1926.354(d).

• Artificial cooling is allowed only if it ensures the temperature of the unstripped metal will not be appreciably raised.
• Cooling methods should be part of the job hazard assessment and documented when used to justify smaller strip areas (see OSHA's PPE hazard assessment requirements).

If the flammability of the preservative coating is already known and documented (for example, via the manufacturer's information or an SDS), a separate site test may not be necessary; the standard requires a test when the coating's flammability is not known. See 1926.354(a).

• Employers should keep SDSs and other documentation on file and use them in the hazard assessment required before hot work.
• If conditions differ from the SDS (e.g., aged coating, weathering, contamination), a competent person should re-evaluate flammability on site.

No; 1926.354(a) does not prescribe a specific test method — it requires that a competent person make a test to determine flammability. See 1926.354(a).

• Because the standard leaves the method to the judgment of the competent person, employers should follow safe, documented procedures (small scrape-and-ignite tests under controlled conditions) and include the test in the hazard assessment.
• For broader employer obligations on performing hazard assessments and documenting PPE needs, see OSHA's PPE hazard assessment requirements.

If a preservative coating is toxic and work will generate fumes or dust, the employer must either strip the coating per the applicable provision or provide appropriate respiratory protection and other controls in accordance with subpart E. See 1926.354(c)(1) and 1926.354(c)(2).

• Conduct a hazard assessment to identify airborne exposures and select controls (local exhaust ventilation, wet methods, or respirators) as needed (see OSHA's PPE hazard assessment requirements).
• When toxic preservatives are known to include regulated contaminants (for example, arsenic), follow hazard communication and training requirements discussed in OSHA's Arsenic-treated wood standard coverage letter of interpretation as applicable.

Employers should perform a competent hazard assessment and then choose the option provided by the standard: in enclosed spaces either strip at least 4 inches or provide airline respirators that meet subpart E, and outdoors provide respirators per subpart E. See 1926.354(c)(1) and 1926.354(c)(2).

• The hazard assessment should consider contaminant toxicity, expected concentrations, duration of exposure, feasibility of stripping, and availability of respirators and engineering controls (see OSHA's PPE hazard assessment requirements).
• Where available, consult SDSs and industrial hygiene sampling to inform the decision.

1926.354 does not explicitly require air monitoring prior to respirator selection; it requires either stripping or providing respirators and that respirators meet subpart E requirements. Employers should, however, perform a hazard assessment that may include monitoring to select appropriate respirators. See 1926.354(c)(1) and OSHA's PPE hazard assessment requirements for guidance.

• Monitoring can be a key part of demonstrating exposure levels and choosing suitable respiratory protection.
• If monitoring is conducted, use the results to document respirator selection and the respiratory protection program elements required under subpart E.

Yes; when a preservative coating contains arsenic or other hazardous chemicals, employers must follow 1926.354's stripping/respirator options and also comply with hazard communication, training, and other applicable OSHA requirements such as those discussed in the arsenic-treated wood LOI. See 1926.354(c) and OSHA's letter on Arsenic-treated wood standard coverage.

• Employers must provide SDSs, labels, and employee training under the Hazard Communication standard for known hazardous coatings (see the arsenic LOI).
• Follow the toxic-preservative provisions of 1926.354 and perform a hazard assessment to determine respiratory protection and other controls.

Except for the explicit 4-inch minimum in enclosed spaces, 1926.354 does not state a fixed numeric stripping distance for toxic coatings; instead, coatings must be removed a sufficient distance to prevent appreciable heating of unstripped metal and to meet the enclosed-space 4-inch rule. See 1926.354(c)(1) and 1926.354(d).

• The competent person must determine sufficient removal distance based on heat input, metal thickness, and cooling methods.
• Employers may use artificial cooling to reduce the cleaned area as permitted by 1926.354(d).

While 1926.354 does not prescribe specific records, employers should document the competent person's flammability and toxicity tests, hazard assessments, respirator selections, and any decisions to strip coatings or use cooling. See 1926.354 and OSHA's guidance on employer hazard assessments in the PPE hazard assessment requirements.

• Documentation should include who performed the test, test method and results, chosen controls (stripping, respirators, cooling), and any monitoring data.
• Written documentation supports compliance and helps protect worker health by ensuring consistent implementation of controls.

If coatings are neither highly flammable nor toxic, 1926.354's specific stripping and respirator provisions do not apply; however, employers must still assess hazards before hot work and take appropriate precautions to protect workers. See 1926.354(a)-(c).

• Even when coatings appear nonhazardous, perform a hazard assessment and follow safe hot-work practices (fire prevention, ventilation, PPE) as recommended in OSHA guidance on hazard assessments (see PPE hazard assessment requirements).
• If conditions change or uncertainties remain, treat the coating as unknown and conduct the competent-person test required by 1926.354(a).

Yes; employers should include preservative-coating hazards in their job hazard analyses and PPE program and document their hazard assessment when PPE will be required. See 1926.354 and OSHA's PPE hazard assessment requirements, which explain employer responsibilities for assessing hazards and selecting PPE.

• The assessment should evaluate flammability and toxicity, determine stripping needs, select respiratory protection, and document any training or monitoring.
• Written certification of the hazard assessment should be retained when PPE is required per OSHA guidance.

Employers should control the release of toxic fumes by stripping coatings where required, using local exhaust ventilation, providing appropriate respirators per subpart E, and implementing administrative controls such as exclusion zones and training. See 1926.354(c) and OSHA's PPE hazard assessment requirements.

• For enclosed spaces, strip or use airline respirators as required by 1926.354(c)(1).
• For open air, provide appropriate respirators based on the hazard assessment per 1926.354(c)(2).

While 1926.354 does not list specific training elements, employers are responsible for assessing hazards of preservative coatings and ensuring employees understand the protections in place (stripping, respirators, cooling, and safe hot-work practices). See 1926.354 and OSHA's PPE hazard assessment requirements for employer duties on hazard assessment and PPE selection.

• Training should cover how coatings are tested for flammability, the meaning of "highly flammable," respirator use (program, fit, maintenance), and procedures for stripping and cooling.
• When coatings are known hazardous chemicals (e.g., arsenic-treated), employers must also comply with Hazard Communication training obligations as explained in OSHA's Arsenic-treated wood standard coverage LOI.

If the employer relies on respirators for toxic coatings, they must follow the respiratory protection requirements of subpart E and conduct a hazard assessment to select appropriate respirators. See 1926.354(c)(1), 1926.354(c)(2), and OSHA's PPE hazard assessment requirements.

• The employer must implement a respirator program that includes selection, medical evaluation, fit testing (when required), training, and maintenance per subpart E.
• For contaminants with special rules (e.g., asbestos), see OSHA's LOI on Respirator selection for asbestos work for examples of stricter agency requirements.

Yes; employers may use artificial cooling (including water or other wet methods) to limit the size of the area required to be cleaned, provided such cooling prevents appreciable heating of the unstripped metal. See 1926.354(d).

• Cooling must be effective enough to keep the unstripped metal below temperatures that would ignite coatings or create toxic emissions.
• Document the cooling method and reasoning in the job hazard assessment to justify reduced stripping areas (see OSHA's PPE hazard assessment requirements).