Toxic and flammable solvent safety

Yes — when toxic solvents are used in a cleaning operation, the operation must be completely enclosed if that is the measure chosen to prevent solvent vapors from escaping into the work area. See the enclosure requirement in 1915.32(a)(1).

• Enclosure is one of three options listed in 1915.32(a) to safeguard employees from toxic solvents; the others are ventilation and respiratory/skin protection.
• A ‘‘completely enclosed’’ cleaning operation means vapors are not allowed to escape into the working space; common examples include closed tanks, enclosed dip tanks with lids, or fully shrouded spray booths.

Yes — either natural ventilation or mechanical exhaust ventilation may be used to remove solvent vapors at the source and dilute them to a safe level for the entire work period, provided the ventilation actually reduces airborne concentrations to safe levels. See 1915.32(a)(2).

• The standard requires ventilation to remove vapors at the source and to dilute vapors in the workspace to a concentration that is safe for the full shift.
• If natural ventilation cannot reliably keep concentrations at safe levels, mechanical exhaust or enclosure must be used instead.

Employers must provide suitable respiratory protection when ventilation and enclosure measures do not keep solvent vapors at safe concentrations for the entire work period. See 1915.32(a)(3).

• The standard says respiratory equipment must meet the requirements of the shipyard respirator rules (subpart I of Part 1915).
• In practice, respirators are required when monitoring or assessment shows workers would otherwise be exposed above safe limits or when engineering controls cannot feasibly reduce exposures enough.
• Remember to also protect skin and eyes with suitable clothing and equipment when necessary, as specified in 1915.32(a)(3).

OSHA will use the principles in the Threshold Limit Values (TLVs) identified in [1915.4] as guidance to define a safe airborne concentration for enforcement purposes. See 1915.32(b) and the general Part 1915 page at 1915.

• This means OSHA may refer to TLVs and other recognized occupational exposure limits when determining what concentration is safe for an entire work period.
• If a chemical lacks an OSHA PEL, employers should use TLVs or other recognized OELs as a practical basis for protecting workers (see also guidance on competent persons in [1915.4] and the competent person Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18 which explains that a competent person may specify protections when there is no PEL).

Employers must take precautions for flammable solvents in accordance with the requirements of [1915.36]. See 1915.32(c) and the flammable-solvent rules at 1915.36.

• This means employers cannot rely only on the toxic-solvent provisions; they must also follow the specific fire and explosion prevention measures, handling, storage, and control practices in [1915.36].
• Even if ventilation or enclosure controls adequately control health hazards, additional safeguards (grounding, bonding, fire suppression, ignition-source control, etc.) required by 1915.36 still apply.

Yes — a competent person may recognize and evaluate exposures without a PEL and specify the necessary protection and precautions to ensure employee safety under Part 1915. See the competent person definition in 1915.4 and OSHA's Letter of Interpretation explaining that competent persons may determine protection when no PEL exists at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.

• The Letter of Interpretation clarifies that where no OSHA PEL exists or where hazards appear below an OSHA PEL, the competent person must still be able to recognize hazards and specify protections.
• Employers must ensure the competent person has the necessary training and authority to set controls (ventilation, enclosure, PPE, work practices) appropriate to the hazard.

Yes — when employers are required to provide personal protective equipment (PPE) such as respirators to comply with 1915.32(a)(3), the employer generally must furnish that PPE at no cost to employees under OSHA's payment rule and related guidance. See 1915.32(a)(3) and OSHA's Letter of Interpretation about employer payment for PPE at https://www.osha.gov/laws-regs/standardinterpretations/2014-11-13.

• The 2007 payment rule and OSHA's interpretation explain that employers must pay for required PPE, with limited exceptions; a deposit system is allowed only if it does not result in an effective cost to the employee.
• Employers must also ensure PPE is appropriate, maintained, and that employees are trained in its use as required by the relevant standards referenced in 1915.32(a)(3).

It means the ventilation system (natural or mechanical) must reduce and keep the airborne solvent concentration at or below a recognized safe level for the full shift or duration of exposure. See 1915.32(a)(2) and the use of TLVs in 1915.32(b).

• ‘‘Safe for the entire work period’’ implies consideration of time-weighted exposure limits (e.g., an 8‑hour TWA) rather than short-term spikes alone.
• Employers should use recognized exposure limits (OSHA PELs where available, or TLVs/OELs per 1915.32(b)) and conduct monitoring to verify the ventilation keeps exposures within those limits.

Employers must provide suitable clothing and equipment to protect employees' skin and eyes from contact with toxic solvents and their vapors when necessary to prevent harm. See 1915.32(a)(3) and OSHA's shipyard eye-and-face protection interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2019-12-30 which discusses appropriate eye protection for specific hazards.

• ‘‘Suitable’’ means PPE that effectively prevents exposure (e.g., chemical-resistant gloves and aprons, splash goggles or face shields rated for chemical splash, and protective coveralls) selected for the solvent(s) in use.
• The eye-and-face protection letter notes that protection must match the hazard (for example, welding filters for intense radiation), so employers must select PPE appropriate to the specific solvent hazard and exposure routes.

If ventilation or enclosure cannot maintain safe solvent vapor concentrations for the full work period, employers must provide suitable respiratory protection and, where necessary, skin and eye protection as required by [1915.32(a)(3)]. See 1915.32(a).

• Employers should also consider changing work practices, reducing task duration, or substituting less hazardous solvents when feasible.
• Any respirators provided must be appropriate to the hazard and used consistent with the applicable respirator program and requirements referenced by 1915.32(a)(3).

The standard requires ventilation to dilute vapors to a safe level, which in practice often requires exposure monitoring or other objective data to demonstrate compliance with safe limits (such as TLVs). See 1915.32(a)(2) and the TLV guidance in 1915.32(b).

• Monitoring may be necessary to verify that concentrations are within safe limits for the entire shift.
• Where OSHA PELs exist employers should sample and compare personal exposures to those limits; where PELs do not exist, employers should rely on TLVs or other recognized OELs as discussed in 1915.32(b) and supported by the competent person guidance at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.

Yes — if a cleaning operation is completely enclosed and engineered so that vapors do not escape into the workspace, and the enclosure plus any ventilation keeps worker exposures at safe levels, respirators may not be required. See 1915.32(a)(1) and 1915.32(a)(2).

• The employer must verify that the enclosure prevents vapors from entering the breathing zone and maintains safe concentrations for the entire work period.
• If the enclosure leaks or cannot be shown to control exposures, then the employer must use additional controls such as respirators per 1915.32(a)(3).

No — 1915.32(b) says OSHA will use the principles in the TLVs when defining safe concentrations in enforcement, but where an OSHA PEL exists that PEL remains the enforceable limit; TLVs are used as guidance, especially when PELs are absent or outdated. See 1915.32(b) and the Part 1915 overview at 1915.

• Employers must comply with OSHA PELs where they exist; TLVs can inform best practices and enforcement decisions when PELs do not adequately address a hazard.

The employer is responsible for protecting employees and ensuring controls are implemented; however, the competent person designated under Part 1915 may specify necessary protections under the employer's authority. See 1915.32 and the competent person definition in 1915.4, as explained in OSHA's Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.

• 1915.4 explains the competent person must be capable of recognizing hazards and specifying necessary protections; the responsibilities are ultimately those of the employer.
• Employers must ensure the competent person has the training, authority, and resources to implement controls (ventilation, enclosure, PPE) required by 1915.32.

When a solvent is both toxic and flammable, employers must meet both sets of requirements: control health exposures under [1915.32] and take fire/explosion precautions required by [1915.36], as stated in [1915.32(c)]. See 1915.32(c) and 1915.36.

• You cannot ignore fire prevention because you control the health hazard, or vice versa — both health and fire risks must be addressed concurrently.
• Examples: use enclosure or ventilation to control vapors (health) while also grounding/bonding, controlling ignition sources, and following storage/handling rules (fire) per 1915.36.

No — 1915.32(a)(2) requires ventilation to dilute vapor concentrations to a level that is safe for the entire work period, so intermittent or short bursts that allow exposures to exceed safe limits during parts of the shift are not acceptable. See 1915.32(a)(2) and the TLV guidance in 1915.32(b).

• Employers should design controls (continuous ventilation, enclosure, or reliable respirator use) so worker exposures do not exceed time-weighted limits over the applicable work period.

No — relying only on worker symptoms is not sufficient; employers must use engineering controls or PPE that keep airborne concentrations at safe levels for the entire work period and should use monitoring or objective data to verify control effectiveness as required by 1915.32(a) and the TLV guidance in 1915.32(b).

• Symptoms can lag exposure and vary by individual; employers must proactively assess and control exposures, not wait for symptoms before taking action.
• Use monitoring, industrial hygiene assessments, or competent person judgments (see 1915.4 and the competent person Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18) to determine protections.

Yes — when respirators are provided to protect employees as required by [1915.32(a)(3)], employers must comply with the applicable respirator program and requirements (e.g., fit testing, maintenance, training) referenced by the regulation. See 1915.32(a)(3).

• While 1915.32(a)(3) refers to respirator requirements in Part 1915, employers should ensure respirators are NIOSH‑approved, properly fitted, maintained, and that users are trained, consistent with applicable respirator rules referenced by the standard.
• Employers must also provide the respirators at no cost consistent with the employer payment guidance at https://www.osha.gov/laws-regs/standardinterpretations/2014-11-13.

Employers should prefer controls in this order: enclosure first (if feasible), then ventilation to remove vapors at the source, and use PPE/respirators when engineering controls cannot reduce exposures to safe levels for the entire work period, as set out in 1915.32(a).

• This hierarchy reflects the standard's listing: (a)(1) enclosure, (a)(2) ventilation, (a)(3) respiratory/skin/eye protection.
• Employers should document why a chosen control is effective (monitoring data, engineering calculations) and consider substitution or process changes when practical to reduce hazards.