01 / Occupational profile
Your MM occupational profile
Engineering-space noise
Common occupational factor
Machinery spaces aboard Navy ships routinely operate at ambient noise levels well above hazard thresholds from turbines, generators, and rotating equipment, and MMs stand extended watches in these spaces.
Asbestos exposure (hull- and era-dependent)
Common occupational factor
Ships commissioned or overhauled before the early 1980s used asbestos-containing lagging, gaskets, and insulation extensively in engineering spaces; MMs performing maintenance on lagged pipes and equipment during that era had direct exposure. Later-generation hulls carry substantially lower risk.
Heat stress in engineering spaces
Common occupational factor
Boiler and engine rooms run at elevated ambient temperatures, and sustained watch-standing or maintenance work in these spaces is a recognized heat-stress exposure.
Fuels, lubricants, and solvent exposure
Common occupational factor
Routine servicing of shipboard machinery involves handling fuels, lubricating oils, and cleaning solvents, sometimes in confined, poorly ventilated spaces.
Ladder-well and hatch transit under load
Common occupational factor
Moving through a ship's engineering spaces requires frequent ladder-well climbing and hatch transits, often while carrying tools or parts, placing repetitive strain on the knees, shoulders, and lower back.
02 / Your service
What did you actually do?
Your MOS is the starting point. Your actual assignment, era, equipment, location, and duties determine which parts of the occupational history are relevant. Use the Evidence Builder below to select your actual duties and see records that may corroborate them.
Machinist's Mates stand engineering watches and perform maintenance on boilers, main engines, reduction gears, pumps, and auxiliary machinery in engine rooms and machinery spaces. These spaces run continuously at high ambient noise levels from turbines, generators, and rotating machinery, and at elevated temperatures from boilers and engines, particularly in spaces without modern climate control. Older hulls commissioned or overhauled before the early 1980s used asbestos-containing lagging, gaskets, and insulation extensively in engineering spaces, and MMs performing maintenance on pipes and equipment lagged with asbestos materials had direct exposure during repair and removal work. Fuels, lubricating oils, and cleaning solvents are handled routinely during equipment servicing, and movement through the ship involves frequent ladder-well and hatch transits, often carrying tools or parts.
Ships built or refitted before the early 1980s widely used asbestos-containing insulation, gaskets, and lagging in engineering spaces. Machinist's Mates who served aboard older hulls, or during major overhauls of them, have a materially different asbestos-exposure profile than those who served exclusively on later-generation ships.
Duties that may vary by assignment
- Standing engineering watches and operating/maintaining boilers, main engines, reduction gears, pumps, and auxiliary machinery
- Working in engine rooms and machinery spaces with sustained high ambient noise from turbines, generators, and rotating equipment
- Performing maintenance and repair in elevated-temperature spaces, particularly around boilers and steam systems
- On older hulls, working around and removing asbestos-containing lagging, gaskets, and insulation during maintenance
- Handling fuels, lubricating oils, and cleaning solvents during routine equipment servicing
- Frequent ladder-well and hatch transits carrying tools, parts, or equipment through confined shipboard spaces
Related historical codes: MMN (nuclear-trained Machinist's Mate); MMA (auxiliary machinery specialty)
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Military Occupational Evidence Builder
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Military service
Navy · MM Machinist's Mate
For another specialty, open its guide from the MOS library. A job code alone does not establish individual duties or exposure.
Era(s) of service
Deployments
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Your Evidence Builder identifies records that may document your service history. If VA has already decided your claim, the next question is different: what did VA accept, what did VA reject, and why?
Request a free decision review03 / Corroboration
Building your occupational history
Records matter because they can connect a job title to an individual's actual work and circumstances.
Engineering-space noise
Records that may corroborate it
- · Hearing-conservation audiograms (DD 2215/2216) and DOEHRS-HC records
- · Sea-service history and ship assignment records identifying engineering-department duty
- · Evaluations describing watch-standing and engine-room assignment
Limit: Documented engineering-space noise exposure supports the event element only. A current hearing-loss disability under 38 CFR § 3.385, or a tinnitus complaint, and a nexus are still required.
Asbestos exposure (hull- and era-dependent)
Records that may corroborate it
- · Sea-service history and ship assignment records establishing hull, commissioning date, and any overhaul periods served aboard
- · Asbestos-medical-surveillance records if enrolled in a shipboard or shipyard program
- · Evaluations or job records describing pipe-lagging repair, boiler maintenance, or overhaul work
Limit: Service aboard an older hull does not by itself establish asbestos-related disease; a current diagnosis (such as pleural disease or asbestosis) and a medical opinion addressing latency and exposure level are required.
Heat stress in engineering spaces
Records that may corroborate it
- · Sea-service history and ship assignment records identifying engineering-department duty
- · Sick call entries for heat-related illness during sea duty
- · Evaluations describing engine-room watch and maintenance duty
Limit: Heat-stress exposure typical of engineering-space duty does not by itself establish a specific current cardiovascular or dermatologic diagnosis.
Fuels, lubricants, and solvent exposure
Records that may corroborate it
- · Evaluations and job records describing machinery maintenance tasks
- · Sick call entries for skin or respiratory irritation complaints
- · Sea-service history establishing engineering-department assignment
Limit: General fuel and solvent exposure typical of the rating does not establish a specific current diagnosis without clinical findings and a nexus opinion addressing the substances involved.
Ladder-well and hatch transit under load
Records that may corroborate it
- · Evaluations describing engine-room and machinery-space duty
- · Sick call and physical therapy entries for knee, shoulder, or back complaints
- · LOD determinations for any documented fall or injury aboard ship
Limit: Typical shipboard movement demands do not by themselves establish that a specific joint was injured in service.
04 / Evidence standard
What your MOS can — and cannot — establish
May help document
Work performed, circumstances of service, consistency of an alleged exposure, and the nature or duration of duties where supported by individual records.
Does not automatically establish
A diagnosis, medical causation, severity, percentage, presumption, or entitlement to service connection.
05 / Medical evidence
Conditions that may be relevant to the occupational history
This is not a list of conditions to claim. A veteran's actual diagnosis and individual service record determine relevance; occupational evidence is not medical causation.
Hearing +
Tinnitus
Why the occupation may matter: Sustained engineering-space noise from turbines, generators, and rotating machinery is a recognized hazardous-noise source.
Records and clinical evidence: A current report of persistent tinnitus and a lay account of onset; audiometric changes support but are not required.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Sensorineural hearing loss
Why the occupation may matter: Cumulative high ambient noise during extended engine-room watches is associated with high-frequency hearing loss.
Records and clinical evidence: Audiometry meeting 38 CFR § 3.385 thresholds, entrance/separation comparisons, and a nexus opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Respiratory / pulmonary +
Pleural disease, asbestosis, and related interstitial lung disease
Why the occupation may matter: MMs who served aboard hulls commissioned or overhauled before the early 1980s may have had direct asbestos exposure during pipe-lagging and boiler maintenance work.
Records and clinical evidence: Sea-service history establishing hull and dates, current pulmonary imaging and function testing, and a medical opinion addressing exposure level and disease latency.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Lung cancer (asbestos- or exposure-related)
Why the occupation may matter: Asbestos exposure aboard older hulls is a recognized risk factor for lung cancer after a substantial latency period.
Records and clinical evidence: Sea-service history, current oncology diagnosis and staging, and a medical opinion addressing exposure and latency.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Lumbar / knees +
Lumbar strain and degenerative arthritis of the knees
Why the occupation may matter: Repetitive ladder-well transit and confined-space maintenance work load the spine and knees over a career at sea.
Records and clinical evidence: Current imaging and range-of-motion findings, sea-service documentation of engineering duty, and a nexus opinion addressing cumulative loading.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Skin +
Contact dermatitis and other skin conditions
Why the occupation may matter: Repeated fuel, lubricant, and solvent contact during machinery servicing can produce irritant or allergic skin reactions.
Records and clinical evidence: Current dermatological diagnosis, documentation of the substances handled, and a nexus opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Cardiovascular +
Hypertension
Why the occupation may matter: Sustained heat stress in engineering spaces has been studied as an occupational cardiovascular stressor, though the association is exposure-dependent and individual.
Records and clinical evidence: Current diagnosis, sea-service documentation of engineering-space duty, and a nexus opinion addressing the specific occupational exposure.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
06 / Exposure record
ILER and toxic exposure
For applicable exposure-related claims, VA may review the Individual Longitudinal Exposure Record (ILER) and a toxic exposure risk activity (TERA) memorandum along with deployment and occupational records. An ILER entry does not automatically establish exposure or service connection.
07 / After a decision
Why a MM claim may still be denied
An exposure finding is not the same as a grant. These are examples from the researched guide, not predictions about a particular case.
VA may accept
A duty or event consistent with the service record
But may deny
A diagnosis, medical relationship, or rating element
Record to examine
Decision findings, service and private treatment records, examination rationale, and medical opinions.
Asbestos claim denied for lack of hull-specific documentation
A claim referencing "shipboard asbestos" generally, without establishing the specific hull, its commissioning or overhaul dates, and the veteran's engineering-space duties, is difficult for VA to evaluate and is often denied absent that documentation.
Noise exposure conceded, hearing claim denied on nexus
VA may accept engineering-space noise exposure, then deny based on an audiologist's opinion citing a normal separation audiogram, which alone does not defeat a hearing claim.
Latency-related denial for respiratory or cancer claims
Asbestos-related disease often manifests decades after exposure. An examiner unfamiliar with that latency period may discount a nexus opinion solely because of the time gap between service and diagnosis.
No current diagnosis for claimed back or knee condition
Chronic pain complaints without a diagnosed disability or functional-impairment evidence under Saunders v. Wilkie are commonly denied at the threshold.
Heat-stress or hypertension claim denied for lack of nexus specificity
General references to "working in a hot engine room" without a medical opinion addressing the specific occupational mechanism are often insufficient to support a cardiovascular claim.
Rating understates severity from a single exam snapshot
A grant may still understate severity when the exam does not account for flare-ups or repetitive-use loss under 38 CFR §§ 4.40, 4.45 and Correia v. McDonald.
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MM questions
Does serving as a Machinist's Mate automatically prove I was exposed to asbestos?
No. Exposure depends on the specific hull, its era and overhaul history, and your engineering-space duties. Documenting your ship's commissioning or overhaul dates alongside your assignment supports the exposure element; a current diagnosis and nexus opinion are still required.
I served on a newer ship — can I still have an asbestos claim?
It's less likely but not automatically ruled out; some legacy components and shipyard periods involved residual asbestos-containing materials even on later hulls. Your specific ship history and job records are what matter.
Does engine-room noise count the same as weapons noise for a hearing claim?
The legal standard is the same — a current disability under 38 CFR § 3.385 and a nexus — but the corroborating evidence differs. Your hearing-conservation audiograms and sea-service history documenting engineering-department duty are the key records.
My asbestos-related disease was diagnosed decades after I got out — does that hurt my claim?
It shouldn't automatically. Asbestos-related disease is recognized as having a long latency period. A denial based solely on the time gap, without an opinion addressing that latency, may be inadequate.
Can Reserve sea duty support an asbestos or noise claim?
It can, depending on duty status. Injuries and diseases incurred during active duty for training are generally treated more favorably than those during inactive duty for training.
Does my heat-stress exposure prove I have hypertension from service?
No. It supports a plausible occupational mechanism, but a current hypertension diagnosis and a medical opinion connecting it to your specific engineering-space duty are still required.
What records best document my specific ship and exposure history?
Sea-service history and ship assignment records showing hull number, commissioning and overhaul dates, evaluations describing your engineering duties, and any asbestos-medical-surveillance records.
Sources and legal references
General education only; not legal or medical advice. Oakridge Claims is a private business, not affiliated with or endorsed by VA. Nothing here establishes a representative-client relationship or guarantees a result. Free accredited VSO help is available.