Every January, somebody at your company has to close out last year's OSHA 300 Log, total it up, and turn it into the OSHA 300A — the one-page summary that goes on the wall. Miss a total, use the wrong headcount for hours worked, or post it a week late, and you've created a citation risk out of paperwork, not out of an actual injury. This is the walkthrough we'd hand a new EHS coordinator doing it for the first time: where each number on the 300A comes from, how TRIR and DART get calculated, who has to sign it, and what "post it" really requires. No guessing — where the rule leaves room for judgement, note it and move on; don't force an answer you can't defend.
What is the OSHA 300A and how is it different from the 300 Log?
The OSHA 300 Log is your running record — one row per recordable case, added as things happen through the year. The 300A is not a new record. It's a roll-up: total deaths, total days-away cases, total restricted-or-transfer cases, total other recordable cases, then the underlying counts (days away, restricted/transfer days, injury and illness types), plus average employment and total hours worked for the establishment. From those last two figures you calculate two rates — TRIR and DART — and print the whole thing on a single certified page.
If you've not worked through how cases land on the 300 Log in the first place, our guide to the OSHA 300 Log covers that groundwork, and OSHA 300 vs 300A vs 301 lays out how the three forms relate. The short version: the 301 (or an equivalent incident report) captures one case's detail within 7 calendar days of you learning about it, that detail gets logged on the 300, and at year end the 300 gets totalled onto the 300A. Every number on the summary should trace back to a line on the log — if it doesn't, something's wrong before you even get to posting.
Step 1: Close out the 300 Log for the year
Before you can total anything, the log for the calendar year has to be finished. That means every recordable case from 1 January through 31 December is entered, classified correctly (days away, restricted/transfer, or other recordable), and any 301 incident reports are filed and match what's on the log. This is also the point to review borderline calls one more time — a case marked "other recordable" that actually involved days away changes both the case-type total and the days total on the 300A. If you're not certain a case belongs on the log at all, run it back through the three-part recordability test — work-relatedness under 1904.5, then whether it's a new case, then whether it meets a recording criterion — rather than leaving it in on a guess.
How do you calculate hours worked for TRIR?
Total hours worked is the single figure most likely to be wrong on a 300A, because it's rarely sitting in one system. It means actual hours worked by all employees at the establishment during the year — payroll hours, not scheduled hours, not hours including paid time off, holidays, or sick leave that wasn't actually worked. If you run shift work, overtime, or seasonal staffing, pull the figure from payroll or timekeeping records for the exact calendar year, not a rounded estimate. Getting this number wrong doesn't just misstate one line — it throws off both rates on the form, since hours worked sits in the denominator of each.
Step 2: Pull the totals onto the form
With the log closed, transfer six category totals plus the case-detail counts. This is arithmetic, not judgement — every figure should already exist on the 300 Log, you're just summing columns.
| 300A field | What it captures | Where it comes from |
|---|---|---|
| Total deaths | Count of fatality cases | 300 Log column G |
| Total cases with days away from work | Cases where the employee missed at least one day | 300 Log column H |
| Total cases with job transfer or restriction | Cases moved to lighter duty or restricted hours | 300 Log column I |
| Total other recordable cases | Recordable cases that didn't involve death, days away, or restriction/transfer | 300 Log column J |
| Total days away from work | Sum of calendar days away across all days-away cases | 300 Log column K |
| Total days of job transfer or restriction | Sum of calendar days on restricted/transfer duty | 300 Log column L |
| Injury and illness type counts | Injuries, skin disorders, respiratory conditions, poisonings, hearing loss, all other illnesses | 300 Log columns M(1)–M(6) |
| Annual average number of employees | Establishment headcount averaged across the year | Payroll or HR records |
| Total hours worked by all employees | Actual hours worked, establishment-wide, for the year | Payroll or timekeeping records |
| TRIR | (Recordable cases × 200,000) ÷ hours worked | Calculated from the totals above |
| DART | (Days-away, restricted, or transfer cases × 200,000) ÷ hours worked | Calculated from the totals above |
| Establishment information | Name, address, industry (NAICS), certifying official | Company records |
The OSHA 300A summary: the fields it asks for and where each one traces back to on the 300 Log.
Days-away cases with a case that's still open at year end need care. If an employee is still out on 31 December, OSHA lets you estimate the days-away count and cap it, but the underlying case still counts once in the case-total column. Don't double it up in next year's totals either — this is a common source of overstated day counts we see when people rebuild a 300A from memory instead of the log itself.
Step 3: Calculate TRIR and DART
Both rates use the same formula shape, scaled to a standard base of 200,000 hours — that's 100 employees working 40 hours a week, 50 weeks a year, which is what makes rates comparable between a 20-person shop and a 2,000-person plant.
TRIR (Total Recordable Incident Rate) = (Number of OSHA recordable cases × 200,000) ÷ Total hours worked by all employees.
DART (Days Away, Restricted, or Transferred rate) = (Cases involving days away, restricted duty, or job transfer × 200,000) ÷ Total hours worked.
Job13's rate calculator runs both from your totals if you'd rather not do the division by hand, and our dedicated posts on TRIR calculation and the DART rate go through the arithmetic and common rounding questions in more depth.
Worked example: a 40-person metal fabricator
Say a small metal fabrication shop closes out its 300 Log for the year with these totals: 1 death (0, none this year), 3 days-away cases, 2 restricted/transfer cases, 1 other recordable case — 6 recordable cases in total. Days away summed to 41 calendar days; restricted/transfer days summed to 18. The shop averaged 40 employees and logged 83,200 total hours worked for the year (roughly 40 people at 2,080 standard hours each, adjusted for a few partial-year hires).
TRIR = (6 × 200,000) ÷ 83,200 = 1,200,000 ÷ 83,200 = 14.4.
DART = (5 × 200,000) ÷ 83,200 = 1,000,000 ÷ 83,200 = 12.0 — five, because 3 days-away plus 2 restricted/transfer cases both count toward DART, while the one "other recordable" case doesn't.
Those numbers go straight onto the 300A alongside the raw counts, the establishment's NAICS code and address, and the certifying official's name and title. Nothing on the form should be a fresh judgement call at this point — it's a transcription and a division problem, provided the log underneath it was built correctly.
Step 4: Who has to sign it?
The 300A has to be certified by a "company executive" — and OSHA defines that narrowly. It's one of: an owner of the company, an officer of the corporation, the highest-ranking company official working at the establishment, or that person's immediate supervisor. A safety coordinator or HR generalist who prepared the form generally can't also certify it unless they hold one of those titles. The certifying signature is a statement that the person has examined the 300A and believes, to the best of their knowledge, that it's accurate and complete — so it's worth a real review, not a rubber stamp, before signing.
Step 5: Post it — where, when, and for how long
Once signed, the 300A gets posted in a conspicuous place where notices to employees are normally displayed — a breakroom noticeboard, a timeclock area, anywhere staff will actually see it. It has to go up by 1 February and stay up through 30 April, covering the prior calendar year's data. That's a fixed three-month window every year, not three months from whenever you happen to finish the paperwork.
Two things trip people up here. First, a zero-recordable year still requires posting — you write zeroes across the case and rate fields and post the form anyway. Nothing happened is itself a fact the rule wants displayed. Second, posting the 300A is a separate obligation from the ITA electronic submission to OSHA — you can owe both, and doing one doesn't excuse the other. We cover the physical posting requirement in more detail, including what counts as "conspicuous," in our OSHA 300A posting requirements post.
If your establishment falls under a partial industry exemption (Appendix A) or has 10 or fewer employees, routine 300 Log and 300A requirements don't apply — but that exemption doesn't extend to a fatality, in-patient hospitalisation, amputation, or loss of an eye, which still has to be recorded if OSHA or BLS asks for it in writing, and separately reported to OSHA within the timeframes in 1904.39. Exemption status is worth confirming rather than assuming, since partially exempt industries shift more often than people expect.
Common pitfalls: where teams get this wrong
- Posting late, or not at all in a zero-recordable year. The 1 February deadline is fixed, and "nothing happened" is not a reason to skip posting — post the zeros.
- Wrong signer. Someone in EHS or HR fills out and signs the form without holding an owner, officer, or top-official title at the establishment. The person who prepares it and the person who certifies it are often two different people.
- Hours worked pulled from the wrong source. Using budgeted or scheduled hours instead of actual payroll hours worked inflates or deflates both TRIR and DART, sometimes by a meaningful margin at a smaller establishment.
- Miscounting open cases at year end. A days-away case still running on 31 December needs an estimate, capped appropriately, without double-counting it again the following year once it closes.
- Treating the 300A total as gospel when the underlying log has errors. A case wrongly classified as "other recordable" instead of "days away" throws off two totals and both rates, and it's easy to miss because the 300A itself looks internally consistent even when it's wrong.
One EHS manager we spoke with put it this way: "The 300A takes ten minutes once the log is right. Every year we lose an afternoon, it's because a case from March got logged wrong and nobody caught it until December." That's the pattern worth guarding against — fix classification at the point of entry, on each case's Form 301, rather than trying to reconcile it during the year-end scramble.
Recordkeeping enforcement has been a live area for OSHA in recent inspection cycles, and the agency's Injury Tracking Application submissions give it a wider dataset than it had a decade ago to spot establishments whose posted totals and ITA-submitted figures don't line up. A 300A that doesn't match what was actually submitted electronically is exactly the kind of discrepancy that draws a follow-up question.
Get the 300 Log right first, then the 300A follows
Every field on the 300A depends on the 300 Log underneath it being accurate — the case classifications, the day counts, the recordability calls made on each individual incident. That's where most 300A errors actually start. Job13's free recordability check walks you through the 1904.7 criteria for any case, citing the exact regulation as it goes, and returns "needs review" instead of guessing when the rule genuinely leaves room for judgement. If you're managing recordkeeping across a full year, Job13 Pro keeps your 300 Log, generates the 300A summary with TRIR and DART calculated automatically, and produces your ITA export when submission season comes around — all built from the same case-by-case determinations, so the numbers on the wall match the numbers you submitted.
Frequently asked questions
Does a company with zero recordable injuries still need to post a 300A?
Yes. An establishment with no recordable cases for the year still completes and posts a 300A, entering zeroes in the case and day totals. Posting isn't conditional on having something to report — it's an annual requirement tied to the calendar, not to the year's injury count.
Who is allowed to sign the OSHA 300A?
Only a "company executive" as OSHA defines it: an owner, a corporate officer, the highest-ranking official at that establishment, or that person's immediate supervisor. Whoever compiles the form isn't automatically qualified to certify it unless they also hold one of those roles.
How long does the 300A have to stay posted?
From 1 February through 30 April of the year following the one it summarises, in a location where employees will see it — a noticeboard, breakroom, or similar conspicuous spot used for other workplace notices.
What's the difference between posting the 300A and submitting it through the ITA?
Posting is physical: a signed paper (or printed) copy displayed at the establishment for the required window. ITA submission is electronic: sending the same data, plus 300 and 301 detail for some establishments, to OSHA through its Injury Tracking Application, generally due 2 March. Check OSHA's current establishment-size and industry thresholds to confirm whether ITA submission applies to you — it's a separate duty from posting, and meeting one doesn't satisfy the other.
How do I calculate TRIR and DART for the 300A?
TRIR is (total recordable cases × 200,000) divided by total hours worked. DART is (cases involving days away, restricted duty, or transfer × 200,000) divided by the same hours-worked figure. The 200,000 base represents 100 employees working a standard full year, which is what makes the rate comparable across establishments of different sizes.
