Hydraulic Injection Injury Statistics

About the datasets

This page draws on three distinct OSHA data systems. They must not be merged into a single time-series or incidence denominator.

Methodology and inclusion rule

Strict tissue-entry inclusion rule

A narrative was included only when it explicitly documents that hydraulic fluid or oil:

• was injected into tissue;
• pierced tissue; or
• was ejected with pressure into tissue and produced a puncture wound.

Narratives describing spray, splash, burns, bruising, abrasions, or lacerations without explicit fluid entry were excluded. Source silence was recorded as “not stated,” not as “no.”

IMIS case-finding process

Candidate records were found through multiple hydraulic-fluid, hydraulic-line, injection, injected, puncture, leak, hose, and related query combinations run against the OSHA Accident Investigation Search tool, supplemented by related-record and title/narrative review. Deduplication was by OSHA Accident Summary Number. All 25 accepted records were read at the narrative level and manually classified. The ★ verification grade in the dataset confirms direct OSHA narrative review.

ITA term-match rule

A record entered the ITA candidate universe when hydraulic or the common misspelling hydrolic appeared, case-insensitively, in at least one of seven fields: job_description, New_incident_location, New_incident_description, New_nar_before_incident, New_nar_what_happened, New_nar_injury_illness, New_nar_object_substance. This produced 721 records nationally and 19 records for Tennessee establishments. Explicit injection cases were then identified by applying the strict tissue-entry rule to each candidate narrative.

Known biases

• OSHA accident narratives are not a complete national injury surveillance system.
• The IMIS search interface is query-dependent; candidate totals contain unrelated mechanisms.
• Severe and officially investigated workplace events are more likely to appear than minor or unreported events.
• The observed hospitalization share in the IMIS set must not be generalized to all hydraulic injection injuries.
• ITA data is employer-submitted; narrative quality varies. Not all establishments or workers are covered.
• The 2025 ITA file covers only incidents submitted through March 15, 2026 and is not the final complete-year file.

Summary statistics — OSHA IMIS case set (n = 25)

All figures are characteristics of the 25 located OSHA IMIS narratives, not national rates.

Release-point breakdown

20 of the 25 located cases (80%) explicitly named the hydraulic component responsible for the fluid release. This does not imply that 80% of all hydraulic injuries are caused by these component types.

Activity breakdown

Worker activity at the time of injury, based on editorial classification of the OSHA narrative. 17 of 25 cases (68%) occurred during work on or around the hydraulic system specifically — not incidental contact during normal operation.

Stated-pressure records

Seven of the 25 IMIS narratives stated a system, tool, or operating pressure. Values ranged from 1,000 to 10,000 psi. These values reflect stated system or tool pressure — they do not measure pressure at the wound site. The absence of a stated pressure in the other 18 records does not indicate low-pressure incidents.

All 25 OSHA IMIS case records

Each row links to the original OSHA accident-detail narrative. “Not stated” means the field was blank or not mentioned in the narrative — it does not mean the event did not occur. ★ = direct OSHA narrative reviewed.

HSE pressure guidance

The UK Health and Safety Executive (HSE) Safety Bulletin FOD 4-2014, “Hydraulic injection injury,” states that serious hydraulic injection injuries have occurred at pressures above 100 bar (1,450 psi), and cites anecdotal evidence of injury occurring around 7 bar (101.5 psi).

The 100 bar figure describes cases where serious injuries have been reported — it is not a threshold below which injection is safe. The 7 bar figure is described by HSE as anecdotal. Neither value was derived from a controlled study of penetration thresholds. The stated-pressure values in the OSHA IMIS case set (1,000–10,000 psi) reflect system or tool pressure stated in the narratives, not pressure measured at the wound.

Scope note: The HSE bulletin covers Great Britain. It is cited here as an official safety-authority document providing the most widely referenced pressure-threshold language in English-language hydraulic injection guidance.

2025 ITA explicit injection cases (n = 4)

Four records in the partial 2025 ITA file (submitted January 1–March 15, 2026) explicitly met the strict tissue-entry rule. These four records are separate from the 25 IMIS historical cases; they must not be added together to produce a combined case total.

National ITA term-match (721 records)

A literal search for hydraulic or hydrolic across seven ITA narrative fields returned 721 records across 52 jurisdictions in the partial 2025 file. This is a record count, not a national injury count or incidence rate. A record appears here when the search term appears in any of the seven specified fields — the injury may be entirely unrelated to hydraulic-fluid injection (e.g., a worker tripped over a hydraulic lift).

Of the 721term-match records, four explicitly met the strict tissue-entry rule. The remaining records described spray or splash exposure, hydraulic-equipment-related impacts or pinches, contact with hydraulic fluid on surfaces, or cases where the word “hydraulic” appeared only in a job title or equipment context field.

State-by-state term-match counts

A zero in the “Explicit injection cases” column means no record in this partial file met the strict tissue-entry rule for that state. It does not mean zero real-world hydraulic injection injuries occurred in that state.

Tennessee detail

The 2025 ITA literal-term search returned 19 Tennessee establishment records. None of the 19 explicitly met the strict tissue-entry rule. A zero explicit injection count for Tennessee applies only to this search rule and this partial, coverage-limited file — it does not mean Tennessee had zero real-world hydraulic injection injuries in 2025.

Tennessee mechanism categories

Editorial mechanism codes were assigned to all 19 records by reviewing the employer-submitted narratives.

Memphis (Shelby County municipality) records

Two of the 19 Tennessee records were reported by establishments whose cityfield was “Memphis” — one of Shelby County's seven incorporated municipalities per the official Shelby County municipality list. The ITA cityfield reflects the reporting establishment's city, not necessarily the incident location. Neither Memphis record met the strict tissue-entry rule.

• Record 2282496 (2025-03-18): Air cargo transportation, Memphis. Hydraulic-fluid spray or splash exposure. Worker removing a vent plug was sprayed in the face with hydraulic fluid and swallowed some fluid. No explicit tissue injection documented.
• Record 2282487 (2025-11-05): Air cargo transportation, Memphis. Hydraulic-fluid surface/contact. Aviation maintenance technician stepped on hydraulic fluid while working on a hydraulic component, lost balance, and fell from a stand — fracturing the lower right leg. No fluid injection documented.

This two-record Memphis count must not be described as a complete Shelby County hydraulic injury count. No dedicated Memphis or Shelby County hydraulic-fluid injection injury count was located in any official source reviewed in this research pass.

All 19 Tennessee records

Data gaps and limitations

• Not national incidence rates.The IMIS case set and ITA counts are not national or state incidence rates. Neither can support statements like “X hydraulic injection injuries occur in the U.S. per year.”
• ITA coverage is incomplete. ITA data is not representative of every establishment or worker; it covers establishments subject to OSHA electronic reporting requirements. The 2025 file covers only incidents submitted through March 15, 2026.
• A zero means “not found by this rule” — not “none occurred.” A zero in a state column means no record matched this exact search rule in this exact file. Real-world injuries may be unreported, described differently, or covered by state-plan agencies not in this file.
• ITA data is employer-submitted. Outcome and day-count fields reproduce employer-submitted OSHA Form 300/301 data. Narrative quality and completeness vary across establishments.
• No Memphis or Shelby County injection count was located. A search across OSHA, Tennessee OSHA (TOSHA), and local records during this research pass did not identify any dedicated Memphis or Shelby County hydraulic-fluid injection injury count. This is a search-limited data gap — it should not be stated as proof that no incidents occurred.
• Refresh schedule.The historical IMIS query is audited quarterly. The ITA extraction is re-run when OSHA updates the 2025 file. The “last verified” date on this page is updated only after source files and row coding have been rechecked.

Dataset download

All datasets are released under CC BY 4.0. The normalized coding and original summaries are supplied for factual research use. Each underlying OSHA record remains attributable to OSHA and is linked at record level. SHA-256 prefix shown for integrity verification.

Frequently asked questions

How many OSHA hydraulic injection injury cases are in this database?

25 OSHA accident-investigation narratives (1991–2020) passed the strict inclusion rule: an official OSHA narrative that explicitly documents hydraulic fluid entering or penetrating tissue, or a direct high-pressure hydraulic-fluid jet causing tissue injury. These are a located case set, not a census of all U.S. hydraulic injection incidents.

What body region is most commonly injured in the located OSHA cases?

23 of the 25 located OSHA cases (92%) involved the hand, palm, thumb, or fingers. One case involved the right foot and one involved the back. This pattern is consistent with the nature of the injury: workers typically contact pressurized hydraulic components by hand during inspection, troubleshooting, or maintenance.

Were most of the located OSHA injection injuries hospitalized?

24 of the 25 located cases were classified by OSHA as hospitalized injuries. However, this figure reflects selection bias in the OSHA accident-investigation narrative system, which is more likely to capture severe, investigated events than minor or unreported incidents. It should not be treated as a national hospitalization rate for hydraulic injection injuries.

What activities were workers doing when they were injured?

17 of the 25 located cases (68%) occurred during maintenance, repair, inspection, leak-finding, hose disconnection, or testing. The remaining 8 occurred during normal equipment operation or other activities. Leak-finding without proper depressurization — including using a rag or bare hand to locate a hose or tube leak — appears in multiple narratives.

At what pressure does hydraulic fluid injection become dangerous?

The UK Health and Safety Executive (Safety Bulletin FOD 4-2014) states that serious hydraulic injection injuries have been reported at pressures above 100 bar (1,450 psi) and cites anecdotal evidence of injury occurring around 7 bar (101.5 psi). Of the 25 located OSHA cases, seven stated a system or tool pressure; values ranged from 1,000 to 10,000 psi. These values reflect stated system pressure, not measured pressure at the wound. Low apparent pressure does not establish a safe threshold.

What is the difference between the IMIS case set and the 2025 ITA data?

The IMIS set (1991–2020) is drawn from official OSHA accident-investigation narratives retrieved through the OSHA Accident Investigation Search tool. The 2025 ITA set is from employer-submitted OSHA Form 300/301 case detail records covering the 2025 incident year (as submitted through March 15, 2026). The two systems have different coverage rules, selection effects, and submission processes. They must not be merged into a single time-series or incidence count.

How many hydraulic injection cases were in the 2025 OSHA ITA data?

A literal search for 'hydraulic' or 'hydrolic' across seven ITA narrative fields returned 740 records nationally. Of those, four records explicitly met the strict tissue-entry rule: fluid injected into tissue, piercing tissue, or ejected with pressure into tissue and producing a puncture wound. Tennessee produced 19 literal-term matches; none of the 19 explicitly met the strict tissue-entry rule. A zero in a state does not mean zero real-world injuries — it means no record matched this exact search rule in this coverage-limited file.

Does this database contain Memphis or Tennessee hydraulic injection injury counts?

No dedicated Memphis or Shelby County hydraulic-fluid injection injury count was located in the official sources reviewed. The 2025 ITA data included 19 Tennessee establishment records; two of those were reported by establishments in Memphis (a Shelby County municipality), but neither met the strict tissue-entry rule. The ITA city field reflects the reporting establishment's city, not necessarily where the incident occurred.

Sources

1. U.S. Occupational Safety and Health Administration. Accident Investigation Search (IMIS). 25 individual accident-detail records reviewed 2026-07-29. Each record-level URL is provided in the OSHA-HFI v1.0 dataset and in Table 5 above. osha.gov/ords/imis/accidentsearch.search_form
2. U.S. Occupational Safety and Health Administration. 2025 ITA Case Detail Data, submitted January 1–March 15, 2026 (partial year). Verified 2026-07-29. osha.gov/sites/default/largefiles/ITA_Case_Detail_Data_2025_through_3-15-2026.csv
3. UK Health and Safety Executive. Hydraulic injection injury. Safety Bulletin FOD 4-2014. Verified 2026-07-29. hse.gov.uk/safetybulletins/hydraulic-injection-injury.htm
4. Shelby County, Tennessee. Cities in Shelby County. Official municipality list used to classify ITA city field values. shelbycountytn.gov/1221/Cities-in-Shelby-County