Veterans filing claims involving burn pits, contaminated water, chemical exposures, or similar hazards will often see the term Toxic Exposure Risk Activity - TERA - in VA materials. The term comes from the PACT Act of 2022, which directed the VA to screen enrolled veterans for toxic exposure concerns and to consider exposure risk activities when developing claims. The VA's PACT Act overview describes the law's exposure framework, and the VA's hazardous materials exposure page lists the exposure categories the VA recognizes.
What a TERA is
A Toxic Exposure Risk Activity is exactly what the name says: an activity during service that carried a risk of toxic exposure. Examples the VA has discussed include serving in a location where open burn pits were used, certain occupational specialties, and duty in listed places during listed periods.
The key point: TERA is a development tool, not a benefit. Documenting that a veteran had a toxic exposure risk activity tells the VA what to look for - it does not by itself establish service connection for any condition.
Two paths: presumptive and direct
The PACT Act expanded the list of presumptive conditions tied to burn pits, Agent Orange, and other exposures. For a presumptive condition, a veteran who served in the covered place and period is presumed to have the in-service element - the VA grants service connection for the diagnosed condition without requiring separate proof of a medical link to the exposure.
For conditions that are not presumptive, the claim follows the ordinary rules. Under 38 CFR 3.303, service connection requires a current disability, an in-service event or exposure, and a relationship between the two. The exposure side may be well documented - the medical link still has to be supported by the evidence. Our guide on what evidence the VA needs walks through how the VA describes that evidence.
Where veterans start
Every case is different, and there is no obligation at any step. When veterans want to understand what their records actually support, these are the two most common starting points:
- Medical records review
A licensed physician reviews your records for a $250 flat fee and identifies which conditions the available evidence may support. The fee is refunded in full if nothing supportable is identified.
- Nexus letter
When the records support one, a licensed provider writes the medical opinion that addresses the link between your condition and your service.
Where the duty to assist fits
The VA's duty to assist, in 38 CFR 3.159, requires the VA to make reasonable efforts to help a claimant obtain evidence - which can include ordering a VA claim exam that includes a medical opinion when the record indicates a possible connection but the evidence is not sufficient to decide.
A documented TERA often plays a role in that analysis: it can be the in-service element that triggers an exam or an opinion request. As our guide on deferred decisions explains, claims involving exposure are frequently deferred while the VA develops exactly this kind of medical evidence.
Where independent medical evidence fits
Because the exposure element is often the easy part for veterans with documented TERA, the disputed question in non-presumptive exposure claims is usually medical: does the current condition relate to that exposure? An independent medical opinion from a qualified physician addresses that question directly, based on the veteran's records.
The strength of any such opinion rests on the same principles covered in our medical evidence guide and the benefit of the doubt article: a reasoned opinion grounded in the records carries more weight than a bare conclusion.
This guide is educational. It summarizes the VA's own published rules and links to the exact sources it relies on. It is not legal or claims advice, and it is not a substitute for an accredited representative, who can advise you about your specific claim. Accredited help is free - search the VA's accreditation database to find a Veterans Service Organization, accredited agent, or attorney.
Frequently asked questions
What is a Toxic Exposure Risk Activity?
A Toxic Exposure Risk Activity, or TERA, is an activity during military service that may have exposed a service member to toxic substances - for example duty in a location with open burn pits, contact with certain chemicals, or work in a listed occupation. The VA uses TERA records and screening to evaluate exposure when developing a claim.
Is TERA a type of VA benefit?
No. TERA is not a benefit or a rating - it is a category of in-service activity the VA considers when developing claims and exams. A disability still must be diagnosed and connected to service under the normal rules in 38 CFR 3.303.
How did the PACT Act change toxic exposure claims?
The PACT Act of 2022 added many presumptive conditions and presumptive exposure locations for burn pits, Agent Orange, and other exposures. When a condition is presumptive, the VA presumes the service connection element for qualifying veterans, so no separate medical nexus opinion is needed for that element.
If my condition is not presumptive, what matters?
For non-presumptive conditions, the claim is decided on the evidence: a current diagnosis, evidence of the in-service exposure, and medical evidence linking the two. That is where medical records and, when the records support one, an independent medical opinion can matter.