TERA Medical Opinions: How VA Evaluates Toxic-Exposure Claims

A veteran can have a documented toxic exposure and a diagnosed illness without qualifying for a presumption of service connection. In some of those cases, a different part of the PACT Act may matter: the requirement for a medical examination and opinion involving a toxic exposure risk activity, usually shortened to TERA.

A TERA medical opinion asks whether a claimed disability is at least as likely as not connected to the veteran's toxic-exposure activity. It can be an important part of a claim, but it is not a presumption, a diagnosis, or a guarantee that VA will grant benefits. Understanding that distinction can make the claim-exam process less confusing.

What “TERA” means

The PACT Act added TERA to federal veterans law in 2022. The statute defines it through military exposure records and other activities that VA determines qualify as toxic-exposure risk activities. In practical terms, the activity may involve environmental or occupational hazards encountered during service, such as airborne hazards, contaminated water, industrial chemicals, radiation, or other potentially toxic conditions. VA organizes these possibilities on its military exposure categories page.

The key word is activity. A TERA is the service event or circumstance involving possible exposure. It is not the medical condition itself, and identifying a TERA does not by itself establish that the activity caused a veteran's illness.

When the law generally requires an exam and opinion

Title 38, United States Code, section 1168 generally requires VA to provide an examination and obtain a medical opinion when all of the following are present:

The veteran has submitted a disability-compensation claim.
There is evidence of a disability.
There is evidence that the veteran participated in a TERA during active military, naval, air, or space service.
The existing evidence is not enough to establish service connection.

The law includes an exception when VA determines there is no indication of an association between the claimed disability and the TERA. That means not every claim mentioning an exposure will result in a TERA opinion. VA may also decide a claim without an in-person examination when the existing medical evidence is sufficient; VA calls this an Acceptable Clinical Evidence, or ACE, review.

A veteran does not schedule a compensation and pension exam independently. After a claim is filed, VA or a VA contractor contacts the veteran if an examination is needed. Our step-by-step toxic-exposure claim guide explains the larger filing process.

What the medical provider must consider

Section 1168 directs the medical provider to consider the veteran's total potential exposure through all applicable military deployments and the combined effect of all of the veteran's toxic exposure risk activities. The legal text does not require the provider to analyze the combined effect of every substance on the separate statutory list of toxic substances and hazards.

The resulting opinion addresses whether a connection between the disability and the TERA is “at least as likely as not.” The examiner supplies medical findings and reasoning; the examiner does not decide the claim. VA adjudicators consider the report with the other evidence in the file, including medical records, military medical and personnel records, test results, and statements from the veteran or others.

A TERA opinion is not the same as a presumption

With a presumptive claim, VA presumes a condition is related to qualifying service when the legal eligibility requirements are met. A TERA opinion instead addresses the medical link in an individual claim when the evidence does not already establish service connection. The opinion may support or weigh against that link, and VA must still decide the claim using the full record.

This distinction is especially relevant when a veteran's diagnosed condition is not on a presumptive list. A nonpresumptive condition can still be considered for direct service connection; it is not automatically excluded merely because it lacks a presumption. Conversely, evidence of a TERA does not mean that every later health condition arose from that exposure.

Do not confuse three different VA processes

VA uses similar exposure language for programs with very different purposes:

Process	Main purpose	Part of a disability claim?
C&P claim exam or TERA medical opinion	Gather medical evidence VA uses to decide service connection and, when applicable, evaluate severity	Yes
Toxic exposure screening	Briefly identify exposure concerns and connect an enrolled veteran with health information or resources	No
Military Environmental Exposures Assessment	Provide an enrolled veteran with a more detailed clinical evaluation of exposure history and health concerns	No; VA says it is not required for a claim, although it may document exposure history

VA's official comparison of claim exams, screenings, and registry evaluations explains the separation between benefits and health programs. Our guide to the VA toxic exposure screening covers the brief health-care screening in more detail.

How to prepare if VA schedules an exam

The exam is for evidence gathering, not treatment. According to VA's current claim-exam guidance, the provider may review the claim file, ask questions, perform an examination, use a Disability Benefits Questionnaire, or request tests. The provider cannot prescribe treatment, make referrals, tell the veteran the claim decision, or provide the final exam results during the appointment.

Make sure VA has current contact information. VA or a contractor may schedule the appointment by mail, phone, or email.
Submit new non-VA medical records before the appointment. An examiner may look at records brought to the exam, but VA says the examiner cannot submit them for the veteran.
Review the service history for accuracy. Be ready to describe duty locations, dates, jobs, and exposure circumstances as accurately as possible. Do not guess when a detail is unknown.
Describe the condition accurately. Explain symptoms, onset, treatment, and functional effects without minimizing or exaggerating them.
Attend or promptly address a scheduling problem. Missing an exam can delay a claim, and VA may decide the claim on the evidence already available. VA's exam page explains how to reschedule and how to report good cause for a missed appointment.

Veterans may submit medical records, military records, and lay evidence. VA's evidence guidance says lay evidence can include a veteran's own statement or a statement from someone familiar with the condition or relevant events. A statement should identify what the person actually observed rather than offer medical conclusions outside that person's knowledge.

After the exam

The provider sends an exam report to VA, and VA reviews it with the rest of the claim file. To obtain the final report, VA instructs veterans to submit a Freedom of Information Act or Privacy Act request using VA Form 20-10206. The report is not obtained directly from the examiner.

Read the eventual decision letter carefully. A denial does not by itself prove that VA made an error, and a favorable medical opinion does not by itself guarantee an award. If the decision appears not to address documented exposure evidence, the required TERA analysis, or a relevant medical opinion, a VA-accredited representative can help review the file and the available decision-review options. The site's appeals helper provides a general starting point, but it is not a substitute for advice about an individual claim.

Why careful review matters

A September 2025 VA Office of Inspector General review identified significant processing problems in an early group of denied, nonpresumptive TERA decisions. The OIG's statistical analysis estimated that 61% of the relevant decisions denied from May 1 through August 31, 2023, had processing errors, some of which could have affected benefits. Examples included failures to identify a toxic-exposure claim, research and verify TERA participation, request an examination and opinion, or include key information in a decision.

That finding has important limits: it concerned denied nonpresumptive TERA-related decisions from a specific four-month period, not all TERA claims, and a processing error did not necessarily mean the claim should have been granted. VA agreed with the OIG's three recommendations. The report supports careful review of the record; it does not support assuming that every denial is wrong.

The practical takeaway

A TERA medical opinion is one route through which VA evaluates whether a nonpresumptive illness may be connected to toxic exposure during service. The strongest preparation is straightforward: file the claim, provide accurate exposure and medical evidence, attend a requested exam, and review the resulting report and decision in context.

Veterans who are still organizing their service history can use the site's exposure check, browse military occupational exposure information, and consult the resources directory. These tools provide education, not medical diagnosis or legal advice.

Primary sources

This page is for informational purposes only and is not medical or legal advice. Consult a qualified professional about your health or benefits.