Do I Need 24-Hour or 40-Hour HAZWOPER Training?

What OSHA's standard requires

HAZWOPER training requirements are established under 29 CFR 1910.120(e) for general site cleanup operations. The regulation does not let workers or employers choose their training level freely — it assigns the required level based on the worker's duties and potential for hazardous substance exposure.

The employer bears the responsibility under the standard for determining which training level applies to each worker's role and ensuring that training — including the hands-on field experience component — is completed before the worker enters the hazardous site.

Who needs the 40-hour HAZWOPER course

The 40-hour course is required for workers who are regularly exposed to hazardous substances and who may face exposure levels at or above permissible exposure limits (PELs). These are workers who are directly involved in the hazardous waste operation — handling materials, operating equipment, or conducting remediation activities on site.

Under 29 CFR 1910.120(e)(3)(i), this group must complete 40 hours of instruction plus a minimum of 3 days of supervised, site-specific field experience before working independently on site.

40-hour course curriculum covers

• Chemical hazard recognition and toxicology
• Site characterization and air monitoring
• Personal protective equipment (PPE) use, selection, and limitations
• Decontamination procedures
• Confined space awareness
• Emergency response procedures and medical surveillance
• Health and Safety Plan (HASP) requirements
• Site-specific hands-on training coordination

Who needs the 24-hour HAZWOPER course

The 24-hour course is required for workers who visit or work occasionally on contaminated sites and are unlikely to be exposed to hazardous substances at or above PELs. These workers have limited or incidental contact with the site and do not directly handle hazardous materials during cleanup or remediation.

Under 29 CFR 1910.120(e)(3)(ii), this group must complete 24 hours of instruction plus a minimum of 1 day of supervised, site-specific field experience.

24-hour course curriculum covers

• Basic hazard communication and toxicology
• PPE awareness and selection
• Site safety and health procedures
• Decontamination basics
• Emergency response awareness
• Site-specific hands-on training orientation

Side-by-side comparison

Which course does your job role require?

If you are unsure which category applies to your role, your employer is responsible for making that determination. When in doubt, the 40-hour course is the more comprehensive qualification and will satisfy requirements for both regular and occasional site work.

The field experience requirement both courses share

Both the 24-hour and 40-hour courses require supervised, site-specific field experience in addition to the online instructional hours. This is not optional — it is a regulatory requirement under 29 CFR 1910.120(e).

The field experience must be arranged by the employer, supervised by a qualified and experienced supervisor, and documented with records showing what tasks were performed and under whose supervision. Online certificates alone — without documented field experience — do not constitute full HAZWOPER compliance for initial 24-hour or 40-hour training.

Read our full guide to the HAZWOPER hands-on training requirement →

What supervisors need — it's more than you might expect

Supervisors who oversee general site workers must complete the same training as the workers they supervise — meaning the full 40-hour course and 3 days of supervised field experience — plus an additional 8-hour HAZWOPER supervisor course covering supervisory responsibilities and safety management.

A supervisor cannot simply take the 24-hour course if their workers are required to take the 40-hour course. The supervisor's training must meet or exceed the training level of the workers under their supervision.

The annual 8-hour refresher — required for both levels

All workers who have completed the 24-hour or 40-hour HAZWOPER course are required by 29 CFR 1910.120(e)(8) to complete an 8-hour refresher course every 12 months. The refresher must occur within 12 months of the previous training to maintain certification.

Unlike the initial 24-hour and 40-hour courses, the 8-hour refresher can be completed fully online without a hands-on component — because workers completing it have already demonstrated initial competency.

If a worker's refresher lapses, the required remediation depends on how long the gap is and the employer's specific requirements. See our guide to expired HAZWOPER certification →

Upgrading from 24-hour to 40-hour HAZWOPER

Workers who have completed the 24-hour HAZWOPER course and whose job duties change to require 40-hour certification do not necessarily need to repeat the full 40-hour curriculum. A 16-hour upgrade course is available to cover the additional content. Workers upgrading will also need to complete the additional field experience to meet the 3-day minimum required for 40-hour certification.

Upgrade eligibility and requirements may vary by employer and jurisdiction. Confirm with your employer or training provider before enrolling in an upgrade course.