VA Disability for Otto Fuel Exposure: Symptoms, Evidence, and Claim Process

Military service often involves sacrifices acutely felt by service members, such as toxic exposure. Unfortunately, most of the time, the consequences of routine work around hazardous substances follow veterans long after their service ends. One such danger is exposure to Otto Fuel II, a propellant used in U.S. Navy torpedoes.

The torpedo fuel is a reddish-orange liquid with a distinct odor, mainly consisting of propylene glycol dinitrate (PGDN), primarily made of chemical compounds designed for use in low-oxygen environments, like submarines.

When the MK 46 torpedo entered service after the chemical's patenting in 1963, it used larger volumes of Otto fuel, increasing the potential health risks for sailors. In the confined spaces on submarines, leaks or fumes increase exposure risks over time, and shift veterans' toxic exposure from earlier hazards to newer chemical risks, especially in the post-Vietnam era. Moreover, exposure to Otto fuel may have occurred without full awareness of its long-term effects for those who worked in close proximity to torpedoes:

• maintenance
• storage
• deployment

Toxic Exposure on Another Level

Service members' Otto fuel exposure primarily occurs through inhaling fumes or direct skin contact, though ingestion is also possible if contamination happens. The highest risks arise in confined spaces where ventilation is limited, and chemicals can accumulate. On ships and submarines, exposure can occur during:

• torpedo handling
• maintenance
• fuel spills

Typical exposure symptoms often appear years after service, and can range from:

• neurological issues
• respiratory problems
• complex chronic conditions

However, because awareness of this exposure has only recently gained attention, many veterans have struggled to connect their health issues to their service time. It further complicates things that even small amounts of Otto fuel exposure can affect the:

• nervous system
• heart
• blood

Most of the torpedo fuel's effects on human health are thought to be caused by its major component, propylene glycol dinitrate (PDGN). Even exposure to levels of PGDN as low as 0.2 ppm in the air for several hours may cause intense headaches in some persons. Statistically, PGDN at 0.2 ppm can alter some brain wave patterns, and at 0.5 ppm, dizziness and nausea are common. Accordingly, exposed sailors have reported:

• headaches
• dizziness
• nausea
• loss of balance
• poor eye-hand coordination
• eye irritation
• severe nose congestion
• difficulty breathing

The most common side effect of PGDN overexposure is headache, which can occur even when the degree is minimal. Based on sailors' experiences, the greater the overexposure, the larger the number of reported symptoms. But it's essential to note that some people who work around Otto Fuel II do get used to being around it, and they do not seem to experience discomfort after a certain period of time. In contrast, people who have worked around Otto Fuel II, but are no longer exposed to this chemical, might feel:

• chest pain
• rapid heartbeat
• heart attacks

According to available medical data, there is no evidence that Otto fuel affects human reproductive ability or causes birth defects. Science has no information yet on whether this chemical suppresses immune response or if it's a carcinogenic substance, and agencies such as IARC, DHHS, and EPA have not classified it as a carcinogen. And, unfortunately, due to the lack of definitive human studies, long-term effects are yet to be determined.

Veterans' Otto Fuel II Exposure Doubled With AFFF Contamination

Some veterans were exposed to both Otto fuel and AFFF, which may complicate medical evaluations and claims, as overlapping toxic effects and unclear exposure timelines can make it more difficult to determine the primary cause of specific health conditions and establish eligibility for compensation or treatment.

Even if the full long-term impact of this chemical exposure remains incomplete, particularly in the confined naval environments, based on BVA decisions and CDC toxicology, exposure to Otto fuel has been associated with a range of health conditions, including:

• neurological issues: chronic headaches, migraines, balance problems, and cognitive impairment
• cardiovascular conditions: coronary artery disease and tachycardia
• respiratory illnesses: bronchitis and asthma

Sporadically, there have also been contamination cases documented with "soaking" clothing or inhaling fumes involving diseases such as:

• chronic kidney disease
• liver disorders

While some case decisions and data suggest possible associations, these findings are not considered final by the VA and do not establish automatic service connection. Otto fuel exposure in the Navy is most commonly reported in positions that involve direct handling of torpedoes and related systems, such as:

• submariners
• torpedoman's mates
• machinist's mates (weapons)
• gunner's mates

In addition to Otto fuel, many sailors were exposed to AFFF firefighting foam, another toxic substance contributing to the overall toxic exposure in service environments. AFFF contains PFAS chemicals associated with kidney cancer and other serious health conditions. In submarines, recirculated air and confined spaces may allow these exposures to overlap, increasing the cumulative chemical burden and risk to organs such as the kidneys.

VA Claims and Direct Service Connection for Otto Fuel II Exposure

When applying for benefits based on Otto fuel exposure, veterans must establish that their current medical condition is connected to their military service. Because Otto fuel is not a presumptive exposure, the VA doesn't automatically accept a connection, meaning that the veteran has to document exposure and provide a medical nexus linking the exposure to the condition. Consequently, exposed veterans must provide:

• Evidence of in-service exposure to the fuel through MOS, service records, ship/submarine logs, or buddy statements from shipmates, relatives, or themselves.
• Documented diagnosis of a condition potentially tied to Otto fuel contamination.
• A medical opinion (VA or private) explaining why it is "at least as likely as not" that the condition was caused by the exposure.

Based on numerous evaluations of veterans' medical and service records, we've noticed a consistent pattern involving exposure to Otto fuel during active duty. It is the case of a career servicemember who reported direct exposure to the substance, followed by documented respiratory symptoms and abnormal pulmonary test results while still in service. The issues persisted over time, and later examinations confirmed residual lung abnormalities. The case reflects how occupational exposure to hazardous chemicals like Otto fuel can lead to long-term health effects, even when initial symptoms appear mild.

While reviewing a considerable number of veterans' claims involving toxic exposures, we could identify a recurring experience of service members who worked regularly with Otto Fuel II. In a Navy veteran's claim, multiple health issues were reported, also because of in-service exposure to Otto fuel: dizziness and breathing problems, heart concerns, and sleep disturbances. These conditions remain under review due to the complexity of toxic exposure effects, underscoring that veterans exposed to substances like Otto fuel develop diverse, hard-to-diagnose symptoms, which then require extensive medical evaluation to determine whether fuel exposures are the underlying cause.

Toxic exposure claims also talk about a common experience around handling Otto fuel while in the military. A long-serving Navy veteran's report of regular exposure to Otto-type torpedo fuel describes short-term effects like headaches during active duty. While such exposure was clearly documented and even recognized as causing temporary symptoms, follow-up medical evaluations consistently showed no lasting or chronic disability linked to the fuel. This reflects a broader pattern where veterans experience immediate effects from Otto fuel exposure, but establishing long-term service-connected conditions remains difficult without clear, ongoing medical evidence.

Toxic Exposure Risk Activity (TERA) Process and Otto Fuel

TERA was created specifically for exposures to hazardous materials that are not officially listed as "presumptive" by law, such as Otto fuel, solvents, pesticides, and other chemical exposures. The VA is required to evaluate toxic exposure through the TERA even if a veteran's diagnosed condition is not presumptive.

However, recognition of exposure under TERA does not guarantee approval of a disability claim. Once exposure is documented, a VA medical examination can evaluate whether a health condition is associated with that exposure. The TERA mechanism requires a medical opinion from the VA showing the potential link between service and disease, rather than automatically presuming a connection. Moreover, the process allows multiple conditions to be considered, including:

• neurological
• cardiovascular
• kidney
• liver
• respiratory

When determining whether there is a service connection, the VA evaluates:

• documented exposure
• timing of symptoms
• scientific evidence

Even if TERA does not guarantee approval ( a medical examiner can still determine that a condition is not related to the exposure), what it does change is the process, shifting it from the veteran having to prove everything independently to VA taking responsibility for investigating and evaluating the connection. In simple terms, direct service connection requires the veteran to build the case, while under TERA - and the VA's Duty to Assist - the agency must help obtain relevant records and provide medical examinations when there is evidence of a possible connection.

While research on Otto fuel is still limited, the VA's processes allow for assessing the potential health effects. Documented occupational exposure, supported by medical evidence and VA examinations, including those conducted under TERA, creates a structured way to evaluate whether a condition is related to service, even without a presumptive connection.

Helping Veterans to Turn Toxic Exposure Into Action

If you're a veteran who worked with or around Otto Fuel II, your experience matters. Even if your symptoms seemed minor at the time or were dismissed as temporary, you shouldn't ignore the signs. The best is to seek medical evaluation, document your exposure, and explore your options through the VA, including TERA-based claims.

Even if it can be a daunting process to navigate the system, with the dedicated help of an experienced attorney, it's worth making steps toward understanding whether your in-service exposure could be affecting your health today. Should you decide to file for compensation, we can help in connecting you with toxic exposure specialists ready to assist with your case.