29 CFR 1910 Subpart Z is the section of federal workplace safety regulations that governs toxic and hazardous substances in general industry. It contains more than 30 individual OSHA standards, numbered 1910.1000 through 1910.1450, covering airborne chemical limits, specific high-risk substances like asbestos and lead, bloodborne pathogens, hazard communication, laboratory chemicals, and worker access to exposure and medical records.1Occupational Safety and Health Administration. Toxic and Hazardous Substances Any employer whose workers might encounter these materials on the job falls under the subpart and must meet the corresponding requirements.
Who Subpart Z Applies To
Subpart Z sits inside 29 CFR Part 1910, OSHA’s general industry standards. If your workplace uses, produces, stores, or generates any of the regulated substances, one or more sections of Subpart Z apply. That covers a wide range of employers: a machine shop grinding chromium alloys, a hospital where nurses handle needles, a construction supply company working with silica products, and a university chemistry lab all fall under different sections of the same subpart.
The first employer obligation is evaluation. You have to determine whether any regulated substances are present in your facility, because that determination drives every downstream requirement — monitoring, training, medical surveillance, recordkeeping, and controls.
Permissible Exposure Limits Under 1910.1000
Standard 1910.1000 is the baseline. It sets the legal ceiling on how much of a given chemical can be in the air workers breathe, organized across three tables.2eCFR. 29 CFR 1910.1000 – Air Contaminants Table Z-1 lists hundreds of individual substances with concentration limits in parts per million or milligrams per cubic meter. Table Z-2 covers a smaller group of substances with more complex exposure profiles. Table Z-3 addresses mineral dusts, including quartz, coal dust, and portland cement.3Occupational Safety and Health Administration. Table Z-3 – Mineral Dusts
Most Table Z-1 limits are expressed as an eight-hour time-weighted average, meaning the average concentration a worker can be exposed to over a full shift without exceeding the legal threshold. Some substances also carry a ceiling value, marked with a “C” in the table, that can never be exceeded at any point during the workday. Where instantaneous monitoring isn’t feasible, the ceiling is assessed as a 15-minute TWA that still cannot be surpassed.4Occupational Safety and Health Administration. 1910.1000 – Air Contaminants
Compliance is measured through air sampling in the worker’s breathing zone. If monitoring shows levels above the PEL, the employer must take immediate corrective action or face citations.
Expanded Standards for High-Risk Substances
For chemicals with well-documented links to cancer, organ damage, or other serious health effects, the general tables aren’t enough. Standards 1910.1001 through 1910.1053 impose additional programs for substances including asbestos, lead, hexavalent chromium, benzene, formaldehyde, cadmium, and respirable crystalline silica.1Occupational Safety and Health Administration. Toxic and Hazardous Substances Each is a self-contained regulatory program with its own PEL, monitoring schedule, medical surveillance requirements, and recordkeeping obligations.
Action Levels
Each substance-specific standard defines an “action level,” a concentration below the PEL that triggers employer obligations before workers reach the legal maximum. The action level is often set at half the PEL, though it varies. For lead, the action level is 30 micrograms per cubic meter of air against a PEL of 50 micrograms.5eCFR. 29 CFR 1910.1025 – Lead Once exposure hits the action level, the employer must begin periodic air monitoring and enroll exposed workers in a medical surveillance program with physical exams and lab work performed by a physician at no cost to the employee.
Regulated Areas and Medical Surveillance
When exposure reaches or exceeds the PEL, the employer must establish regulated areas that only authorized, properly equipped workers can enter. The substance-specific standards also require specialized training, detailed exposure monitoring records, and ongoing medical evaluations that track health changes over time. For asbestos, the PEL is 0.1 fiber per cubic centimeter of air as an eight-hour TWA.6eCFR. 29 CFR 1910.1001 – Asbestos
Hazard Communication (1910.1200)
Standard 1910.1200, commonly called the “Right to Know” rule, requires employers to tell workers what chemicals they’re exposed to and how to handle them safely. It applies to any workplace where employees may contact hazardous chemicals during normal operations or foreseeable emergencies.7eCFR. 29 CFR 1910.1200 – Hazard Communication
Every employer must develop and maintain a written hazard communication program at each workplace. It has to describe how the employer handles container labeling, maintains safety data sheets, and trains employees, and it must include a complete list of all hazardous chemicals present, referenced by the same product identifiers used on the corresponding safety data sheets.8Occupational Safety and Health Administration. Hazard Communication The program must also address how workers will be informed about hazards during non-routine tasks, like cleaning chemical reactor vessels or working near unlabeled pipes.
Chemical manufacturers and importers must evaluate the hazards of every product they make or bring into the country and provide a safety data sheet for each one. These sheets follow a standardized 16-section format covering the chemical’s properties, health hazards, safe handling procedures, and emergency measures. Employers must keep them accessible to workers at all times during their shifts.
Shipped containers must carry labels with the product identifier, signal word, hazard statements, pictograms, and precautionary information. When chemicals are transferred into secondary containers at the worksite, those containers must also be labeled with either the full shipped-container information or at minimum the product name and general hazard information. Portable containers filled for immediate use by the same employee who performed the transfer are the one practical exception.8Occupational Safety and Health Administration. Hazard Communication
Bloodborne Pathogens (1910.1030)
Standard 1910.1030 protects workers who face occupational exposure to blood and other potentially infectious materials. That primarily means healthcare workers, first responders, and laboratory personnel, but it also reaches janitorial staff and anyone else whose job puts them in contact with human blood or body fluids.9Occupational Safety and Health Administration. Bloodborne Pathogens
The centerpiece is the written Exposure Control Plan. Every employer with exposed workers must create one and review and update it at least annually. The plan must identify every job classification with occupational exposure, describe the methods used to reduce that exposure (engineering controls like sharps containers, work practice changes, PPE), and lay out procedures for evaluating exposure incidents. The exposure determination must be made without factoring in whether the worker wears protective equipment; you assess the risk as if the gloves aren’t there.9Occupational Safety and Health Administration. Bloodborne Pathogens
Employers must also offer the hepatitis B vaccination series to every worker with occupational exposure, at no cost, within 10 days of their initial job assignment. The employer cannot require antibody screening as a condition of receiving the vaccine. If a worker initially declines but changes their mind later, the employer must still make the vaccination available as long as the worker remains occupationally exposed.10Occupational Safety and Health Administration. Hepatitis B Vaccination Protection
The Laboratory Standard (1910.1450)
Standard 1910.1450, often called the “Lab Standard,” recognizes that laboratory work involves different risks than large-scale industrial processes. Labs use small quantities of many different chemicals, often in ways that change from day to day, so the standard industrial approach of substance-by-substance PEL compliance isn’t practical.
Instead of applying each individual substance-specific standard, the Lab Standard requires employers to develop and implement a written Chemical Hygiene Plan. This plan must describe the procedures, equipment, protective gear, and work practices the lab uses to protect employees from hazardous chemicals in that specific workplace.11Occupational Safety and Health Administration. 1910.1450 – Occupational Exposure to Hazardous Chemicals in Laboratories The employer must designate a Chemical Hygiene Officer qualified by training or experience to provide technical guidance on the plan.
The general PELs from 1910.1000 still apply in labs, meaning air concentrations of listed chemicals cannot exceed the table values. The monitoring, medical surveillance, and recordkeeping requirements, however, come from the Chemical Hygiene Plan rather than from each individual substance-specific standard.
Access to Exposure and Medical Records (1910.1020)
Standard 1910.1020 gives workers the legal right to examine and copy records related to their workplace chemical exposure and medical evaluations.12Occupational Safety and Health Administration. 29 CFR 1910.1020 – Access to Employee Exposure and Medical Records Covered records include air monitoring data, results from medical exams required under the substance-specific standards, and any analyses of that data. Employers must provide access within 15 working days of a request and must furnish copies at no cost to the employee or their designated representative.13GovInfo. 29 CFR 1910.1020 – Access to Employee Exposure and Medical Records
Retention periods are long because the diseases these substances cause can take decades to appear. Medical records for each employee must be preserved for the duration of employment plus 30 years. Exposure monitoring records must be kept for at least 30 years as well. Conditions like mesothelioma or chronic beryllium disease may not show symptoms until 20 or 30 years after exposure, and the retention rules are built around that reality.
When an employer goes out of business, the records don’t disappear with the company. The employer must transfer all covered records to the successor employer, and the successor must receive and maintain them.14eCFR. 29 CFR 1910.1020 – Access to Employee Exposure and Medical Records If there is no successor employer, the company must notify affected current employees of their right to access the records at least three months before ceasing operations.
Controls and Respiratory Protection
When a hazardous substance exceeds safe levels, employers can’t just hand out respirators. OSHA requires controls in a specific order, from most to least effective:
- Elimination: remove the hazardous substance from the process entirely.
- Substitution: replace the hazardous material with something less dangerous.
- Engineering controls: install ventilation, enclose the process, or redesign equipment to reduce exposure.
- Administrative controls: change work schedules, rotate jobs, or adjust procedures to limit time spent near the hazard.
- Personal protective equipment: respirators, gloves, and other gear as the last line of defense.
Respirators are only appropriate when engineering controls aren’t feasible or while they are being installed. When respirators are necessary, the employer must run a written respiratory protection program covering respirator selection, medical evaluations to confirm the worker can physically wear the equipment, fit testing for tight-fitting respirators, training on proper use and maintenance, and regular evaluation of the program’s effectiveness. A designated program administrator must oversee everything, and all of it must be provided at no cost to the worker.15Occupational Safety and Health Administration. Respiratory Protection
Penalties for Violations
OSHA adjusts its civil penalty amounts annually for inflation. As of the most recent adjustment (effective January 2025), the maximum penalties are:16Occupational Safety and Health Administration. OSHA Penalties
- Serious violation: up to $16,550 per violation.
- Other-than-serious violation: up to $16,550 per violation.
- Willful or repeated violation: up to $165,514 per violation.
- Failure to abate: up to $16,550 per day the hazard continues past the abatement deadline.
A single OSHA inspection of a facility with multiple Subpart Z violations, such as overexposure to a regulated chemical, missing medical surveillance records, and an incomplete hazard communication program, can generate six-figure penalties quickly. Violations of the substance-specific standards in the 1910.1001–1910.1053 range tend to draw higher penalties than general air contaminant violations because the health effects are well-established and the compliance requirements are spelled out in detail.