The 100-employee OSHA 300 and 301 case-detail rule: who's affected

OSHA's 100-employee case-detail rule applies to establishments that had 100 or more employees at any time during the previous calendar year and are in one of OSHA's designated Appendix B industries. Those establishments submit Form 300A plus case-level information from Forms 300 and 301.

This is separate from the familiar 20-249 employee Form 300A rule and the 250+ employee Form 300A rule. It is an establishment-level test, not a company-wide test.

The official rule is 29 CFR 1904.41. OSHA's designated-industry list for this case-detail obligation is Appendix B to Subpart E.

The short test

Ask four questions for each establishment:

1. Did the establishment have 100 or more employees at any time during the previous calendar year?
2. Is the establishment required to keep OSHA injury and illness records?
3. Is its industry classification listed in OSHA's Appendix B case-detail industry list?
4. Does the filing year require annual electronic submission by March 2 of the following year?

If the answer is yes, prepare the 300A summary and case-detail data from the 300 log and 301 incident reports for electronic submission.

What "100 employees" means

The 100-employee threshold is based on the establishment, not the whole enterprise. A company with 900 employees across 12 sites can have only three sites over the threshold. A single 140-person plant can be covered even if the corporate office is small.

OSHA also counts employees who worked at the establishment at any time during the calendar year. That includes full-time, part-time, seasonal, and temporary workers for the headcount test. The practical check is peak employment during the covered year, not the average headcount on December 31.

What gets submitted

Covered Appendix B establishments submit more than the annual 300A totals. They also submit information from:

• OSHA Form 300, the Log of Work-Related Injuries and Illnesses
• OSHA Form 301, the Injury and Illness Incident Report

OSHA does not require every personally identifying field in that case-detail upload. Under 1904.41, the submitted Form 300 data excludes the employee name column. The submitted Form 301 data excludes employee name, employee address, physician or health-care-professional name, and the facility name and address if treatment was provided away from the worksite.

That still leaves sensitive case data. Before anyone certifies the filing, the case list should reconcile to the 300A totals, dates should be in the covered year, and privacy-case handling should be reviewed.

Industries commonly affected

Appendix B is a specific OSHA industry list. It includes many high-injury or high-volume sectors, including:

• Crop and animal production, logging, fishing, and related support activities
• Water, sewage, and other systems
• Foundation, structure, and building exterior contractors
• Food, beverage, wood, plastic, rubber, concrete, metal, machinery, vehicle, ship, and furniture manufacturing
• Motor-vehicle, lumber, metal, grocery, alcohol, and durable-goods wholesalers
• Grocery stores, building-material dealers, auto-parts stores, department stores, and warehouse clubs
• Air transportation, trucking, buses, postal service, couriers, and warehousing
• Waste collection and waste treatment
• Hospitals, nursing care, residential care, and vocational rehabilitation
• Performing arts, spectator sports, amusement parks, traveler accommodation, RV parks, and special food services

Do not rely on a broad label like "manufacturing" or "healthcare." The Appendix B question turns on the establishment's specific business activity and OSHA classification. A related facility in a different classification can have a different answer.

How this differs from the 20-249 rule

The 20-249 employee rule is about Form 300A electronic submission for certain high-hazard industries. The 100-employee rule is narrower in one way and broader in another:

• It starts at 100 employees, not 20.
• It uses Appendix B, not the Appendix A list used for 20-249 employee 300A filing.
• It requires case-detail information from Forms 300 and 301, not just the 300A summary.
• It can apply even when the establishment is already filing 300A for another reason.

The 250+ employee rule is different again: if an establishment has 250 or more employees and must keep OSHA records, it generally submits Form 300A. But the extra 300/301 case-detail upload still depends on the 100+ Appendix B test.

Common mistakes

• Checking company-wide headcount only. Run the test by establishment.
• Using the wrong Appendix. Appendix A and Appendix B are different lists.
• Assuming the 300A filing covers everything. Appendix B establishments need case-detail data too.
• Waiting for OSHA to notify you. Routine annual filers generally are not individually notified.
• Ignoring zero-case years. A covered establishment still submits a 300A even if it had no recordable cases; the case-detail file is a separate data question.
• Mixing State Plan and federal assumptions. OSHA says electronic-submission requirements apply in State Plan States, and some states add their own requirements.

What to prepare before filing

For each establishment, keep a short audit packet:

• Legal company name and establishment name
• EIN used by the establishment
• Establishment address and industry classification
• Peak employee count during the covered year
• Completed 300A summary
• Reconciled 300 log and any 301 incident reports required for the case-detail upload
• Notes explaining any privacy cases or excluded personal fields

The filing checker helps sort the size, business activity, and deadline questions. If the checker shows your establishment is covered, RegFile keeps the review, signer approval, and filing evidence in one place.

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This is informational, not legal advice - verify against your adopted rule.