The threshold question every other Part 1904 determination assumes: is this employer required to keep OSHA injury and illness records at all? Run this FIRST for any small employer or any establishment that may be in a partially exempt industry — otherwise the chain will confidently instruct them to make 300-Log entries for a log they need not keep. Two things are commonly got backwards: the size exemption is measured across the ENTIRE COMPANY, not one establishment (1904.1(b)(1)), and it uses PEAK employment during the last calendar year, not an average or year-end figure (1904.1(b)(2)). A written request from OSHA or BLS under 1904.41/1904.42 defeats the exemption. CRITICALLY, the exemption is PARTIAL: 1904.39 severe-injury reporting binds every employer covered by the OSH Act regardless — an exempt employer still owes OSHA the 8-hour fatality call. Supply establishment_naics_code and the tool resolves the 1904.2 industry question itself against the closed Appendix A list, matching on the first four digits. Reference and triage only.

Decide WHOSE OSHA 300 Log a case belongs on when the injured person is not a straightforward payroll employee — a temp, a leased or supplied worker, a contractor's employee, someone self-employed, or an owner. Run this FIRST whenever the injured person is not on the employer's payroll: if the answer is 'the other employer' or 'no one', the rest of the chain is not this employer's obligation. The controlling test is DAY-TO-DAY SUPERVISION, not who issues the paycheck (1904.31(b)(2)-(b)(3)): a temp on an agency's payroll whose work you direct daily is your case to record. Self-employed people are not covered by the OSH Act at all (b)(1)), and owners or partners of a sole proprietorship or partnership are not employees for recordkeeping (a)). Every payroll category counts — part-time, seasonal and migrant workers included. 1904.31(b)(4) requires the case be recorded exactly once, never on both employers' logs. Reference and triage only — not legal advice.

Determine whether an injury or illness is work-related — the gate every other Part 1904 determination depends on. 1904.5(a) presumes work-relatedness for anything arising from the work environment unless one of the nine closed exceptions in 1904.5(b)(2) applies. Run this BEFORE osha_assess_recordability and pass its work_related result through. Returns one of three verdicts: work_related, not_work_related, or requires_judgment — the last when the regulation itself calls for the employer's evaluation (unclear origin under 1904.5(b)(3), travel status, working at home) or when an exception's 'solely' requirement is not established. Treat requires_judgment as a question to put to the user, never as a licence to pick. Reference and triage only — not legal advice.

Determine whether an injury or illness is a NEW case or a continuation of one already on the 300 Log — the second condition of the 1904.4(a) conjunction. Run this after osha_assess_work_relatedness and before osha_assess_recordability, and pass its new_case result through. Key distinctions it settles: a recurrence CAUSED by a workplace exposure is a new case (1904.6(b)(2), e.g. an occupational asthma episode), while a chronic illness whose symptoms recur WITHOUT exposure is recorded only once (1904.6(b)(1)). A PLHCP recommendation, once sought, is binding and overrides the rule logic (1904.6(b)(3)). Returns work_case verdicts of new_case, not_new_case, or requires_judgment — the last when PLHCP opinions conflict or causation is unestablished. Treat requires_judgment as a question for the user, never as a licence to pick. Reference and triage only — not legal advice or a medical determination.

Decide whether a work restriction or job transfer actually counts as restricted work — not every restriction does. Run this BEFORE passing 'restricted_work_or_transfer' as an outcome to osha_assess_recordability, because getting it wrong moves cases onto or off the 300 Log. The rules it applies: a restriction confined to the day of injury does not count (b)(4)(iii); reduced output while still doing all routine functions does not count (b)(4)(vi); a restriction that misses every routine function does not count (b)(4)(iv), where routine functions are activities performed at least once per week (b)(4)(ii); a partial shift does count (b)(4)(v); and a job transfer is recorded in the same column (b)(4)(ix)-(x)). Critically, when a vague recommendation such as 'light duty' cannot be clarified with the PLHCP, the case MUST be recorded as restricted work (b)(4)(vii)) — the regulation resolves that doubt toward recording. Reference and triage only — not legal advice.

Compute whether an audiogram produces a recordable hearing loss. Two tests must BOTH be met and, critically, in the SAME ear: a Standard Threshold Shift of 10 dB or more averaged at 2000, 3000 and 4000 Hz against the employee's baseline (1904.10(b)(1)), and a total hearing level of 25 dB or more above audiometric zero on the current audiogram (1904.10(a)). An STS in one ear and a 25 dB level in the other does not record. Pass raw audiogram values and the tool does the arithmetic — do not compute averages yourself. If the employee has had a prior recordable hearing loss, pass the REVISED baseline (b)(2)(i)). Age adjustment from Tables F-1/F-2 of 1910.95 appendix F applies to the STS test only, never to the 25 dB test (b)(3)). A retest within 30 days that does not confirm the STS defeats the case; one that confirms it starts a 7-day recording clock (b)(4)). A PLHCP determination of no work-relatedness ends it entirely (b)(6)). Reference and triage only — not legal advice.

Determine whether a work-related injury or illness is OSHA recordable under the 1904.4 decision tree: work-related AND a new case AND meeting either the general recording criteria of 1904.7 OR a specific-case criterion of 1904.8-1904.12 (needlestick, medical removal, hearing loss, tuberculosis). Map the incident narrative to the controlled inputs. The tool applies the closed first-aid list in 1904.7(b)(5)(ii) deterministically and returns a cited determination. Reference and triage only — not legal advice or a medical determination. If the result has determination_final=false, it is provisional: follow the clarification_required instruction, ask the user, and call this tool again with their answer.

Determine whether a fatality, in-patient hospitalization, amputation, or loss of an eye must be reported to OSHA, and compute the actual reporting deadline (8 hours for a fatality, 24 hours for the others) from when the employer learned of it. Also checks the eligibility window from the incident. Datetimes must be full ISO 8601. Applies the 1904.39(b)(11) amputation definition (a severed ear, avulsion, degloving or chipped tooth is NOT an amputation), the (b)(10) rule that a hospitalization for observation or diagnostics alone is not reportable, and the (b)(3)-(b)(4) exclusions for public-road motor vehicle accidents outside construction work zones and events on commercial or public transport. Every one of those still leaves the case RECORDABLE. Reference and triage only — not legal advice.

For a recordable case, determine the correct OSHA 300 Log outcome column (G death, H days away, I job transfer/restriction, J other recordable) using the most-serious-outcome rule, the injury/illness type column, and the day counts capped at 180. Check on_log first — it is false when the case is not recordable. Medical removal cases must be days-away or restricted, never column J, and a removal following a chemical exposure goes in the poisoning column (1904.9(b)(1)); a tuberculosis case goes in the respiratory condition column (1904.11(a)), and may be lined out on the three kinds of evidence 1904.11(b)(2) enumerates. Run osha_assess_recordability first. Reference and triage only.

Determine whether a recordable case is a privacy concern case, meaning the employee's name must NOT be entered on the OSHA 300 Log. 1904.29(b)(7) is a closed list — injury to an intimate body part or the reproductive system, sexual assault, mental illness, HIV/hepatitis/tuberculosis, a contaminated needlestick or sharps cut, and other illnesses where the employee voluntarily asks to be left off. 1904.29(b)(8) forbids treating anything else as a privacy case. Returns the required log entry and the confidential-list and redaction obligations that follow, plus the only three recipients who may receive the forms with identifying information intact (1904.29(b)(10)). Run this after a case is determined recordable.

Decide WHICH establishment's OSHA 300 Log a recordable case belongs on — the last question about an individual incident, and one multi-site employers routinely get backwards. Under 1904.30(b)(4) the case follows the PLACE, not the person: an injury occurring at one of the employer's establishments is recorded on THAT establishment's log even when the employee normally works elsewhere, while an injury away from all of them (a customer site, in transit, remote work) goes on the log of the establishment where the employee normally works. Also reports whether the destination needs its own log — required for establishments expected to operate a year or longer (1904.30(a)), optional for short-term sites which may share a combined log (b)(1) — and, when records are kept centrally, the 7-calendar-day transmission deadline and the two conditions central recordkeeping depends on (b)(2)). Reference and triage only — not legal advice.