TERA stands for toxic exposure risk activity. It is a term from the PACT Act of 2022, not a separate law and not a list of conditions. When your claim includes evidence of a disability and evidence that you took part in a TERA, 38 U.S.C. 1168 can require VA to get a medical exam and opinion before it denies the claim.

A toxic exposure claim does not end because a condition is missing from a presumptive list. There are three different paths:

  1. Presumptive service connection. Qualifying service plus a listed condition replaces the need to prove the medical link. The lists are on the presumptive conditions page.
  2. Direct service connection. Evidence can still show that a specific exposure caused a condition when no presumption applies.
  3. TERA exam and opinion. Under section 1168, VA may have to get a medical exam and nexus opinion when the evidence shows a disability and TERA participation but is not enough to grant the claim.

As of November 8, 2026, VA has proposed TERA regulations (Federal Register, October 1, 2024) but has not issued a final rule, so the rules below come from the statute and VA's claims guidance.

What is a TERA?

A toxic exposure risk activity is any activity that requires an entry in an exposure tracking record system, such as the Individual Longitudinal Exposure Record (ILER), or that VA determines qualifies when it considers what is reasonably prudent to protect veterans' health (38 U.S.C. 1710(e)(4)(C), which section 1168 adopts). VA's manual treats exposure to environmental and military occupational hazards as a type of TERA (M21-1 VIII.iii.9.A).

VA's guidance tells claims staff to read the evidence liberally, apply reasonable doubt, and concede TERA participation when it is consistent with the places, types and circumstances of your service, including your job (VBA Letter 20-24-06). Your own statement, or statements from people who served with you, can establish the exposure when they fit the facts of your service (M21-1 VIII.iii.9.B). VA's manual gives an example: a veteran reports that their duties involved fuel, the personnel records show fuel systems maintenance, and VA concedes the fuel exposure as TERA participation.

Two limits apply. A military job title alone is not TERA participation, and name-only entries in an exposure record, or entries from contractor or civilian service periods, do not count.

What "TERA participation conceded" means

A conceded TERA means VA accepts that you took part in the activity. It is not a finding that the exposure caused your condition; the exam and opinion answer that question. You may see the phrase in the favorable findings of a decision letter, or as a "TERA Conceded" tag next to a condition on the rating code sheet in your claims file.

When VA verifies an exposure, claims staff document it, and every other TERA, on a TERA Memorandum (M21-1 VIII.iii.9.B). The memorandum and the exam request show what VA accepted and what it asked the examiner.

A favorable finding in a decision binds later VA decision makers unless they show it was a clear and unmistakable error (38 CFR 3.104(c)). So a conceded TERA usually settles the in-service exposure. What is often left is the medical link between that exposure and your diagnosis.

Is TERA a presumptive list?

No. A presumption covers listed conditions in listed places. TERA covers what the lists miss. A condition does not have to appear on any list for the TERA exam rule to apply, and a condition that is not presumptive can still be granted on a direct basis. If you are looking for the PACT Act, Agent Orange, Gulf War, radiation or Camp Lejeune lists, use the presumptive conditions checker.

When VA must order a TERA exam and medical opinion

Under 38 U.S.C. 1168(a), when your claim includes evidence of a disability and evidence that you took part in a TERA, and that evidence is not enough to grant service connection, VA must give you a medical exam and ask whether it is at least as likely as not that the disability is linked to the TERA.

That bar is lower than VA's general duty to examine. VA's guidance explains the difference: the general rule calls for an exam when VA cannot decide the claim, and section 1168 calls for one whenever VA cannot grant it. Unless an exception applies, VA must get the exam and opinion before it denies a TERA-related condition.

The examiner must consider your total potential exposure across all your deployments and the combined effect of all your toxic exposure risk activities (38 U.S.C. 1168(a)(2)).

TERA exceptions: when VA can skip the exam

Section 1168(b) lets VA skip the exam when it determines there is no indication of an association between your disability and the TERA. VA's June 12, 2024 guidance (VBA Letter 20-24-06), which VA's claims manual still cites, lists six situations:

  1. Conditions from physical trauma that are not presumptive: blunt force, repetitive use or penetrating injuries. Penetrating injuries that left toxic embedded fragments do not fall under this exception, and hearing loss is not treated as physical trauma.
  2. Mental disorders, meaning any condition in the mental disorders section of the rating schedule (38 CFR 4.130). VA says these should be considered on a direct or secondary basis.
  3. Conditions the Secretary has found have no positive association with herbicide exposure, when herbicide is the only TERA. VA still has to look for any other TERA in your record.
  4. Conditions that began in service, where no nexus opinion is needed, or whose cause is clearly unrelated to toxic exposure. VA tells staff to err on the side of caution and order the exam when in doubt.
  5. The only TERA evidence is an exposure-record entry that does not show an activity with potential exposure, such as a routine health visit.
  6. The only TERA evidence is a self-reported exposure-record entry that cannot be substantiated.

VA's manual adds that a circumstance-based exception should not be applied just because an ILER entry notes potential exposure to toxic substances (M21-1 VIII.iii.9.B). An exception to the exam rule is also not, by itself, a reason to ignore a separately supported direct or presumptive theory.

Build the exposure history

Do not rely only on the phrase "toxic exposure." Describe the facts VA can verify:

  • Dates and locations of service
  • Unit, duty assignment, military occupation and daily tasks
  • The substance, hazard or exposure route when known
  • How often, how long and how intense the exposure was, and what protective equipment you had
  • Deployment, personnel, occupational health, registry or line-of-duty records
  • Statements from people who served in the same setting
  • When symptoms started, and when you were diagnosed and treated

VA may use deployment records, personnel records, the ILER, exposure memoranda or other federal sources. Those systems can be incomplete. A detailed statement helps VA know what to look for without asking you to prove facts that are already in federal records.

What to check in a TERA medical opinion

  • The diagnosis the examiner addressed matches the one you claimed.
  • The exposure history matches what VA conceded, across all your deployments.
  • The examiner considered the combined effect of all your exposures.
  • The opinion explains its reasoning instead of only checking a box.
  • The examiner did not reject the claim only because the condition is not presumptive, since presumptive rules are not meant to limit direct service connection (38 CFR 3.303(d)).
  • The opinion addressed favorable medical evidence and your own statements.

The C&P exam guide covers how to read an exam report.

If VA conceded TERA but denied your claim

This is a common result: the decision lists TERA participation as a favorable finding, then denies the condition. Read the reasons for the denial and find out which of these happened.

  • VA denied without an exam. Look for the exception the decision named and check whether it fits your facts. If VA skipped the exam and no exception applies, that may be a duty to assist error. A Higher-Level Review does not accept new evidence, but the reviewer can send the claim back to fix a duty to assist error that existed when VA decided it.
  • The exam opinion was negative. Check the opinion against the list above. If it rests on a wrong exposure history, a wrong diagnosis or no real reasoning, those are the points to answer. New and relevant evidence, such as a private medical opinion that explains the link, goes in a Supplemental Claim.
  • The opinion was favorable but VA still denied. Compare the decision's reasons with the opinion. A favorable opinion that VA did not weigh is worth raising in a review.

If VA denied the same condition before a new presumption or another change in law, you may need to file a Supplemental Claim. Do not assume VA will reopen every earlier denial on its own.

What to do now

  1. File or preserve an Intent to File if you have not filed yet.
  2. Identify the condition and the most specific exposure facts you have.
  3. Gather service, personnel, deployment, occupational and medical records.
  4. Check every presumption that might apply, using current VA sources.
  5. If no presumption applies, build direct medical evidence instead of dropping the claim.
  6. Review any TERA memorandum, exam and opinion for factual accuracy.

Common mistakes

  • Treating every toxic exposure claim as a PACT Act presumptive claim
  • Assuming a conceded exposure proves that the exposure caused every diagnosis
  • Leaving the exposure statement too vague to verify
  • Missing an earlier denial that may need a Supplemental Claim
  • Accepting an opinion that says "not presumptive" without addressing direct causation
  • Relying on an old, undated copy of a condition or location list

Claim Raven next step

Attach your decision in Ask Raven's Understand a VA letter task to see what VA conceded and why it denied, then use Find gaps in my evidence to compare those reasons with the records you have. If the missing piece is the medical link, the nexus letter guide explains what a private opinion needs, and Raven Nexus can draft one from your records for your clinician to review and sign. These tools do not establish exposure or provide a medical opinion.

Official sources