The OSHA 300 Log is the form employers use under 29 CFR 1904 to list every recordable work-related injury and illness for the year. Each case gets one line, a companion 301 report captures the details, and a 300A summary totals the year for posting.
Most people meet the 300 Log the hard way: an auditor asks for it, or a serious injury forces the question of whether last quarter's cases were logged correctly. The rules are not complicated, but they are exact, and small habits (calling a recordable case "first aid," or forgetting to post the summary) turn into citations. This post walks the three forms, the recordability decision, days-away versus restricted cases, and the posting and submission deadlines under OSHA recordkeeping rule 1904. It is educational, not legal advice.
What is the OSHA 300 Log, and how do the 300A and 301 fit in?
The OSHA 300 Log is one of three linked recordkeeping forms, and knowing which does what keeps you from mixing them up. The Form 300 is the Log of Work-Related Injuries and Illnesses: a running list where each recordable case gets a single line with the employee, the injury, and how it was classified. The Form 301 is the Injury and Illness Incident Report, one filled out per recordable case with the detail behind that line. The Form 300A is the Annual Summary: the year-end totals from the log, which is the form you physically post for workers to see.
Employers with more than ten employees at any point in the year must keep these records unless they fall in a partially exempt low-hazard industry. You must enter each recordable case on the 300 Log and complete a 301 within seven calendar days of learning that it happened. An equivalent form (many plants use their EHS software's output) is allowed as long as it has the same information and is as readable.
What counts as a recordable injury or illness?
A case is recordable when it clears three gates in order: it is work-related, it is a new case, and it crosses at least one recording threshold. Work-related means an event or exposure in the work environment caused or contributed to the condition, or significantly aggravated a pre-existing one. A new case means the employee has not previously had a recorded case of the same condition, or has fully recovered from the last one. Only after both of those do you look at severity.
The recording thresholds are the part people get wrong. A case is recordable if it involves death, days away from work, restricted work or transfer to another job, or medical treatment beyond first aid. It is also recordable on its own if it involves loss of consciousness, or a significant injury or illness diagnosed by a physician or other licensed health care professional, such as a fracture or a punctured eardrum. The dividing line most arguments turn on is "medical treatment beyond first aid," because OSHA publishes a specific, closed list of what counts as first aid. If the treatment is on that list (a bandage, a non-prescription-strength medication, a tetanus shot), it is first aid and not recordable. If it is off the list (stitches, prescription medication, physical therapy), it is medical treatment and the case is recordable.
How do you classify days away versus restricted duty?
Once a case is recordable, you classify it into exactly one of four outcome columns on the 300 Log, and you always record the most serious outcome. This classification is what feeds your injury rate math so getting it right matters beyond the log itself.
| Case classification | 300 Log column | What it means |
|---|---|---|
| Death | Column G | The injury or illness resulted in the employee's death. Report a work-related fatality to OSHA within eight hours. |
| Days away from work | Column H | The employee missed one or more full calendar days after the day of injury. Count the calendar days away and cap the count at 180. |
| Job transfer or restriction | Column I | The employee could not do their routine job functions or was moved to another job, but did not miss full days away. Count the restricted or transfer days, capped at 180. |
| Other recordable case | Column J | Recordable (for example, stitches or a diagnosis) but with no days away, restriction, or transfer. |
Two rules trip plants up. First, you count calendar days, not scheduled workdays, and you begin counting the day after the injury. Second, if a case starts as restricted duty and later becomes days away, you move it to the more serious column and stop double-counting. A case lives in one column at a time. Both the days-away count and the restricted-days count share the same 180-day cap.
How do you fill out the OSHA 300 Log, step by step?
Work the same sequence for every case so nothing gets skipped under time pressure.
- Confirm the case is recordable by walking the three gates: work-related, new case, and past a recording threshold. If it stops at first aid, log it in your internal tracking but not on the 300.
- Complete a Form 301 (or equivalent) within seven days, capturing what the employee was doing, what happened, the object or substance involved, and the treatment.
- Add one line to the 300 Log, assigning a case number and entering the employee's job title, the date, and where the event occurred.
- Describe the case in plain terms (the part of the body and what happened, such as "right hand, laceration from sheet-metal edge") so the entry is understandable a year later.
- Classify the outcome into one column (G, H, I, or J), recording the most serious outcome and the day counts where they apply.
- Check privacy protection, leaving the name off the log and using "privacy case" on the separate list for cases OSHA designates as privacy concern cases, such as certain injuries to intimate body parts.
- Update the line if the case changes, because an outcome can worsen after you first log it, and the log must reflect the final classification.
- Total the columns at year end to build the 300A summary, then certify, post, and store the records.
If you feed the log from incident data your team already captures, most of this is transcription rather than investigation, which is exactly the point of tying it to your near-miss and incident reporting so a recordable case never gets discovered months late.
When do you post the 300A and submit electronically?
Two clocks run every year. The posting clock: a company executive certifies the 300A summary, and you post it where employee notices normally go from February 1 through April 30, covering the prior calendar year. You post the 300A even in a year with zero recordable cases; the summary just shows zeros. The submission clock: covered establishments electronically submit their data to OSHA's Injury Tracking Application during the January 2 to March 2 window.
Which data you submit depends on size and industry. Establishments with 250 or more employees, and those with 20 to 249 employees in designated higher-hazard industries, submit their 300A summary information. As of the 2024 rule change, establishments with 100 or more employees in certain designated high-hazard industries must also submit the more detailed information from their 300 Logs and 301 reports, not just the summary. Confirm your establishment's size class and industry against the current OSHA guidance before each cycle, because the thresholds are specific.
What do the numbers and rules say?
The recordkeeping requirements are set by regulation, not custom, and these are the anchors:
- Recording, posting, retention, and electronic submission are governed by 29 CFR 1904.29 and the broader OSHA recordkeeping rule.
- You must enter a recordable case within seven calendar days of receiving information that it occurred.
- The 300A summary is posted from February 1 through April 30 and records are retained for five years.
None of this is optional, and none of it is hard once the incident data is clean at the source. The failures are almost always upstream: a recordable case logged as first aid, or a case that surfaces long after the seven-day window.
Where the log falls apart
The OSHA 300 Log rarely fails because someone misread the rule. It fails because the injury data lives in three places at once: a paper report on a clipboard, a text to a supervisor, and a memory nobody wrote down. By the time the log is assembled at year end, the seven-day clock is a fiction and the classifications are guesses. Harmony is an AI-native layer that connects machines, software, and paperwork into one operational layer, with no rip-and-replace. Incident reports, treatment records, and restricted-duty notes become structured data captured on a tablet where the injury happened, part of the everyday shape of connected worker technology so the recordable case is visible the day it occurs, not the quarter it is audited.
Harmony is not a recordkeeping product and it does not replace your EHS system or your judgment about what is recordable. It keeps the underlying incident record from being a piece of paper nobody can find, so the log, the TRIR calculation and the inspection file all draw from the same clean source. See what that looks like on a real plant floor in the CLS case study. Keep your broader program honest with a periodic workplace safety audit so the log reflects what actually happens on the floor.