Laboratory hazardous chemical exposure

The standard applies to all employers engaged in the laboratory use of hazardous chemicals. Employers must follow the laboratory standard when their operations meet the definition of "laboratory use of hazardous chemicals" described in 1910.1450(a)(1) and the definitions in 1910.1450(b). Employers whose work does not meet the laboratory-use definition must comply with the relevant OSHA standards in 29 CFR part 1910, subpart Z.

For laboratories, the laboratory standard generally replaces other Subpart Z health standards except for the requirement to meet the specific Permissible Exposure Limit (PEL). Specifically, 1910.1450(a)(2) says the lab standard supersedes other Subpart Z requirements for laboratory uses, but 1910.1450(a)(2)(i) preserves the obligation to keep exposures below the PEL from any other OSHA health standard unless that standard says otherwise. Note: where an OSHA health standard specifically prohibits eye or skin contact, that prohibition still applies under 1910.1450(a)(2)(ii).

If employee exposures routinely exceed the action level (or the PEL if there is no action level), the employer must follow the exposure monitoring and medical surveillance provisions of the relevant OSHA standard. 1910.1450(a)(2)(iii) requires application of paragraphs (d) (monitoring) and (g)(1)(ii) (medical surveillance) of the laboratory standard when exposures routinely exceed the action level or PEL for an OSHA-regulated substance.

Laboratory uses that truly provide no potential for employee exposure are not covered by the lab standard. 1910.1450(a)(3)(ii) gives examples such as "Dip-and-Read" chemically impregnated test media and fully self-contained commercial kits (e.g., pregnancy test kits) where all reagents are contained in the kit. If the procedure cannot expose employees to hazardous chemicals, follow the relevant Subpart Z standard instead of the lab standard.

A "hazardous chemical" for the lab standard is any chemical classified as a health hazard or as a simple asphyxiant under the Hazard Communication Standard. The definition in 1910.1450(b) refers directly to the Hazard Communication Standard at 1910.1200 for the classification criteria for health hazards and simple asphyxiants.

A Chemical Hygiene Officer is an employee designated by the employer who, by training or experience, provides technical guidance for developing and implementing the Chemical Hygiene Plan. The CHO definition and role are set out in 1910.1450(b); the employer must designate a qualified individual to advise on laboratory safety and ensure the Chemical Hygiene Plan meets the standard's requirements.

A Chemical Hygiene Plan must be written and able to protect employees from health hazards in that laboratory and capable of keeping exposures below the PELs. 1910.1450(e)(1) requires the CHP to (i) protect employees from health hazards and (ii) keep exposures below the limits in 1910.1450(c). The CHP must include procedures, equipment, PPE, and work practices appropriate for the lab.

The Chemical Hygiene Plan must be readily available to employees, employee representatives, and, upon request, the Assistant Secretary. 1910.1450(e)(2) requires employers to make the written CHP accessible so staff and authorized representatives can review laboratory safety procedures and controls.

A "laboratory-type hood" is a five-sided enclosure with a moveable sash (or fixed partial enclosure) that draws air from the lab to prevent contaminant escape and allows manipulations without inserting any part of the body except hands and arms. The definition and the restriction on inserting only hands and arms are in 1910.1450(b). Walk-in hoods qualify if sashes are adjusted during use so airflow and exhaust are not compromised and employees do not work inside the enclosure while hazardous chemicals are released.

"Laboratory scale" excludes workplaces whose function is to produce commercial quantities of materials. The lab-scale exclusion and the definition's focus on non-production activities are found in 1910.1450(b). If an operation is intended to produce commercial quantities or simulates production, it falls outside the laboratory-use definition and must follow the relevant Subpart Z standards.

Employers must measure employee exposure when there is reason to believe exposures routinely exceed the action level or, if there is no action level, the PEL. 1910.1450(d)(1) requires initial monitoring for substances regulated by standards that require monitoring whenever such a belief exists. The employer should base that belief on observations, previous measurements, or known hazards associated with the operation; initial monitoring must follow the relevant procedures in the applicable OSHA standard.

If initial monitoring shows exposures above the action level (or the PEL if no action level exists), the employer must immediately comply with the exposure monitoring provisions of the relevant standard. 1910.1450(d)(2) requires follow-up action such as periodic monitoring, engineering controls, and any medical surveillance or recordkeeping specified in the applicable OSHA standard.

Monitoring may be terminated in accordance with the relevant OSHA standard for that substance. 1910.1450(d)(3) directs employers to follow the termination criteria in the specific substance standard (for example, criteria found in a particular Subpart Z standard) before stopping periodic exposure monitoring.

Employees must be notified in writing of their monitoring results within 15 working days after the employer receives the results. 1910.1450(d)(4) allows notification either individually in writing or by posting results in a location accessible to affected employees and requires timely communication of exposure data.

A "select carcinogen" is a substance that is regulated by OSHA as a carcinogen, listed as "known to be carcinogens" by the NTP, classified Group 1 by IARC, or meets animal-tumor criteria in IARC Groups 2A/2B or NTP reasonable anticipation with specific dose thresholds. The full definition and dose criteria appear in 1910.1450(c). 1910.1450(b) and related paragraphs explain that employers should use a designated area for work with select carcinogens, reproductive toxins, or highly toxic substances to control exposure.

"Protective laboratory practices and equipment" are procedures, practices, and equipment accepted by lab health and safety experts as effective in minimizing employee exposure, or that the employer can demonstrate to be effective. See the definition in 1910.1450(b). Appendix A to the standard (non-mandatory) provides guidance to help employers develop a Chemical Hygiene Plan and identify accepted practices and engineering controls such as fume hoods, glove use, and safe procedures.

The lab standard does not apply to uses of hazardous chemicals that do not meet the definition of "laboratory use," such as operations that are part of a production process or simulate production; those activities must comply with the relevant Subpart Z standard. 1910.1450(a)(3)(i) requires employers to identify whether their processes are research/lab scale or production-scale and follow the appropriate OSHA standards.

Appendix A is non-mandatory guidance intended to assist employers in developing a Chemical Hygiene Plan that meets 1910.1450(e) requirements. While employers are not required to follow Appendix A verbatim, it provides practical examples and recommended controls that help ensure the CHP is capable of protecting employees and keeping exposures below PELs.

A "designated area" is a location (it can be the entire lab, a specific area, or a device like a lab hood) where work with select carcinogens, reproductive toxins, or highly acutely toxic substances may be performed. The definition and purpose are in 1910.1450(b). Employers should use designated areas when they have procedures or substances that require extra controls to protect employees, such as limiting access, using specialized engineering controls, and providing particular PPE and work practices.

The Chemical Hygiene Plan must include standard operating procedures that describe safe ways to do laboratory tasks involving hazardous chemicals. Employers must document these SOPs as required by 1910.1450(e)(3)(i).

• Write step‑by‑step procedures for routine operations that use hazardous chemicals (e.g., preparing solutions, weighing powders, using volatile solvents).
• Include the safety and health considerations in each SOP (e.g., ventilation, required PPE, spill response steps).
• Make SOPs readily available to affected employees and train employees on the SOPs as part of the Chemical Hygiene Plan training called for in 1910.1450(f).

Cite: 1910.1450(e)(3)(i).

Employers must use defined criteria to select control measures such as engineering controls, PPE, and hygiene practices to reduce employee exposures. That selection process is required by 1910.1450(e)(3)(ii).

• Follow the hierarchy of controls: first consider engineering controls (e.g., fume hoods, local exhaust), then administrative controls and work practices, and finally personal protective equipment.
• Give special attention to chemicals that are known to be "extremely hazardous"; document why a particular control was chosen and how it will be implemented and monitored.
• Where OSHA exposure limits exist, use monitoring data to decide if additional controls are needed; if no PEL exists, use recognized recommended exposure limits.

Cite: 1910.1450(e)(3)(ii).

The Chemical Hygiene Plan must require that fume hoods and other protective equipment function properly and describe specific measures to ensure their adequate performance. This requirement is in 1910.1450(e)(3)(iii).

• Include procedures for routine checks (e.g., daily visual checks of sash position and airflow indicators) and a schedule for formal performance testing and certification.
• Describe who is responsible for maintenance, how malfunctions will be reported, and steps to stop work if a hood is not operating correctly.
• Document training for employees on correct use of hoods (sash height, work placement) as part of the plan and training requirements in 1910.1450(f).

Cite: 1910.1450(e)(3)(iii).

The Chemical Hygiene Plan must specify the circumstances under which a particular laboratory operation, procedure, or activity needs prior approval from the employer or designee. That requirement is found at 1910.1450(e)(3)(v).

Common situations employers typically require prior approval for include:

• Procedures that use "particularly hazardous substances" (select carcinogens, reproductive toxins, or highly acutely toxic agents) or large quantities of hazardous chemicals.
• Non‑routine or scaled‑up experiments, pilot‑plant work, or work outside a standard laboratory setting.
• Procedures that require specialized containment, air monitoring, or medical surveillance.

Document the approval process (who approves, what documentation is needed, and any required engineering controls or training) in the Chemical Hygiene Plan.

Cite: 1910.1450(e)(3)(v).

For particularly hazardous substances the Chemical Hygiene Plan must include provisions such as designated areas, containment devices, waste removal procedures, and decontamination when appropriate, as listed in 1910.1450(e)(3)(viii).

• 1910.1450(e)(3)(viii)(A): Establishment of a designated area (e.g., a controlled lab room or cabinet).
• 1910.1450(e)(3)(viii)(B): Use of containment devices such as fume hoods or glove boxes.
• 1910.1450(e)(3)(viii)(C): Procedures for safe removal of contaminated waste.
• 1910.1450(e)(3)(viii)(D): Decontamination procedures.

Include specific triggers for when these measures apply and how they will be enforced and documented in the Chemical Hygiene Plan.

Cite: 1910.1450(e)(3)(viii).

The employer must review and evaluate the Chemical Hygiene Plan at least once a year and update it as necessary. This annual review requirement is stated in 1910.1450(e)(4).

• The review should check that SOPs, control measures, training, and monitoring remain effective and reflect current work practices.
• Update the plan whenever there are changes in procedures, personnel, new hazards, or after incidents such as spills or exposures.

Cite: 1910.1450(e)(4).

Employers must provide information and training when an employee is first assigned to a work area with hazardous chemicals and before an employee is assigned to new exposure situations, with refresher frequency determined by the employer. These timing rules are found in 1910.1450(f)(1)–(2) and 1910.1450(f)(2).

• Initial training must cover hazards present in the employee’s work area and the employer’s Chemical Hygiene Plan.
• Provide additional training before tasks that create new exposures (e.g., new chemicals, new procedures, or scaled‑up experiments).
• Employers decide how often to provide refresher training, based on changes in operations, incident history, or observed gaps in knowledge or practices.

Cite: 1910.1450(f)(1)–(2).

Employees must be informed of the contents of the laboratory standard, where the employer’s Chemical Hygiene Plan is located, exposure limits, signs and symptoms of exposures, and where to find reference materials such as safety data sheets. These requirements are listed in 1910.1450(f)(3)(i)–(v).

• 1910.1450(f)(3)(i): Make the standard and appendices available to employees.
• 1910.1450(f)(3)(ii): Tell employees where the Chemical Hygiene Plan is kept.
• 1910.1450(f)(3)(iii): Communicate OSHA PELs or recommended exposure limits if no PEL exists.
• 1910.1450(f)(3)(iv): Describe signs and symptoms of chemical exposures.
• 1910.1450(f)(3)(v): Provide location of SDSs and other hazard reference materials.

Cite: 1910.1450(f)(3).

Employers must provide medical consultation or examinations when an employee develops signs or symptoms of exposure, when monitoring shows exposures above the action level or PEL for OSHA‑regulated substances, or after spill/incident events that could cause hazardous exposure. This is required by 1910.1450(g)(1)(i)–(iii).

• If an employee reports symptoms that could be from a workplace chemical, provide an appropriate medical exam.
• If exposure monitoring shows routine levels above an action level (or PEL when no action level exists), establish medical surveillance per the specific OSHA standard.
• After spills, leaks, explosions, or similar events that could have caused exposure, provide affected employees an opportunity for medical consultation to determine if an exam is needed.

Cite: 1910.1450(g)(1)(i)–(iii).

All medical examinations and consultations must be performed by or under the direct supervision of a licensed physician, provided at no cost to the employee and on paid time; the employer must give the physician the identity of chemicals, a description of exposure conditions (including monitoring data), and a description of signs/symptoms. These requirements appear in 1910.1450(g)(2) and 1910.1450(g)(3)(i)–(iii).

• Provide the physician with the identity of the chemical(s) the employee may have been exposed to.
• Provide a description of the conditions under which the exposure occurred, including quantitative exposure data if available.
• Describe the signs and symptoms the employee is experiencing.
• Ensure the exam/consultation is at a reasonable time and place and without loss of pay.

Cite: 1910.1450(g)(2) and 1910.1450(g)(3).

The employer must obtain a written physician's opinion that includes any recommendation for medical follow‑up, results of the exam/tests, any medical conditions that increase risk from workplace chemicals, and confirmation the employee was informed of results; the opinion must not include unrelated diagnoses. This is required by 1910.1450(g)(4)(i)–(ii).

• The written opinion should state recommendations for further medical follow‑up and results of examinations and tests.
• It must identify any medical conditions discovered that could increase the employee’s risk from exposure.
• The physician must confirm the employee was informed of examination results and any necessary treatment, but must not reveal unrelated diagnoses.

Cite: 1910.1450(g)(4).

When respirators are necessary to keep exposures below permissible limits, the employer must provide appropriate respiratory equipment at no cost and must follow the Respiratory Protection standard [1910.134]. This is stated in 1910.1450(i) and the selection/use direction is reinforced by 1910.134.

• Provide, fit‑test, and train employees on respirator use when engineering and administrative controls cannot keep exposures below the PEL or recommended limit.
• Respirator programs must meet the requirements of 1910.134 including medical evaluation, fit testing, training, and maintenance.
• Respirators must be provided at no cost to employees.

Cite: 1910.1450(i) and 1910.134.

Employers must ensure labels on incoming containers are not removed or defaced, keep safety data sheets readily accessible to laboratory employees, and evaluate lab‑made substances for hazard status and apply the standard accordingly. These duties are in 1910.1450(h)(1)(i)–(ii) and 1910.1450(h)(2)(i)–(iii).

• Do not remove or deface labels on incoming hazardous chemical containers: see 1910.1450(h)(1)(i).
• Maintain and make SDSs readily accessible to lab employees: see 1910.1450(h)(1)(ii).
• For chemicals developed in the lab: if composition is known, determine if hazardous and train per 1910.1450(f); if composition is unknown, assume hazardous and implement the Chemical Hygiene Plan; if producing for others, comply with the Hazard Communication Standard, 1910.1200.

Cite: 1910.1450(h)(1)–(2).

Employers must create and maintain accurate records of exposure measurements and all medical consultations and examinations required by the standard, and ensure those records are kept, transferred, and made available as required by [1910.20]. This is required by 1910.1450(j)(1)–(2).

• Keep records of any monitoring (air sampling, etc.) used to assess employee exposure.
• Keep medical records and written physician opinions generated under 1910.1450(g).
• Manage record retention, transfer, and employee access in accordance with 29 CFR 1910.20.

Cite: 1910.1450(j) and 1910.20.

The Chemical Hygiene Plan must designate personnel responsible for implementing the plan, including assignment of a Chemical Hygiene Officer and, if appropriate, a Chemical Hygiene Committee. This is required by 1910.1450(e)(3)(vii).

• Name the Chemical Hygiene Officer and describe their duties (e.g., overseeing SOPs, ensuring training, arranging medical consultations, coordinating inspections and maintenance of engineering controls).
• If used, describe the role of a Chemical Hygiene Committee and how it will advise on policy, review incidents, and recommend changes.
• Include contact information and authority for stopping unsafe work and ordering corrective actions.

Cite: 1910.1450(e)(3)(vii).

If a chemical produced in the laboratory is a byproduct whose composition is not known, the employer must assume it is hazardous and implement the Chemical Hygiene Plan for work with that substance. This is required by 1910.1450(h)(2)(ii).

• Treat the substance as hazardous until analysis shows otherwise, and apply appropriate engineering controls, PPE, and waste/disposal procedures in the Plan.
• Provide affected employees with information and training per 1910.1450(f).
• Document your hazard evaluation and any monitoring you perform; update procedures if the composition becomes known.

Cite: 1910.1450(h)(2)(ii).