Your client took shrapnel in Kandahar Province while running a supply convoy for a defense contractor. The carrier denies compensability, arguing the injury arose from a "personal errand" because the claimant stepped outside the wire during an unscheduled stop. Without Section 20(a) of the Longshore and Harbor Workers' Compensation Act, your client would need to prove every element of the claim from scratch. With it, the carrier has to dismantle a statutory presumption that Congress built to protect workers exactly like your client.
Section 20(a) is the single most powerful procedural tool in DBA litigation. It flips the default. Instead of the claimant carrying the full burden of proving work-relatedness, the statute presumes the claim is compensable the moment the claimant establishes a prima facie case. The carrier then must produce substantial evidence to rebut that presumption, or the claim proceeds.
ClaimTrove's index of 5,022 OALJ decisions includes 433 that directly address the Section 20(a) presumption. Those decisions reveal consistent patterns in how administrative law judges apply the doctrine, how carriers attempt to rebut it, and where claimant attorneys most often win or lose. This article breaks down the mechanics so you can use the presumption aggressively and anticipate the carrier's playbook.
What Does Section 20(a) Actually Require from the Claimant?
Section 20(a) of the LHWCA (33 U.S.C. Section 920(a)), incorporated into DBA claims through 42 U.S.C. Section 1651, states: "In any proceeding for the enforcement of a claim for compensation under this chapter it shall be presumed, in the absence of substantial evidence to the contrary, that the claim comes within the provisions of this chapter." That single sentence has generated decades of litigation.
The claimant's initial burden is deliberately low. You need to establish two things. First, a harm or injury exists. Second, a working condition or employment event could have caused or aggravated that harm. Courts call this the "prima facie" case, and it requires far less than proof by a preponderance of the evidence.
The BRB has repeatedly held that the claimant need only show a "potential" connection between employment and the injury. A treating physician's opinion that work activities "could have" contributed to the condition is typically sufficient. Even the temporal proximity of an injury occurring during work hours on a military base may satisfy this threshold.
Once the prima facie case is established, the Section 20(a) presumption attaches. The claim is presumed compensable. The burden then shifts entirely to the employer and carrier. This burden-shifting mechanism is what makes the presumption so valuable. Without it, your client in Kandahar would need to affirmatively prove that the convoy assignment, the route, and the specific moment of injury were all within the scope of employment. With it, the carrier must prove they were not.
DBA practitioners should note that the presumption applies to every element of the claim, not just causation. It covers the existence of a disability, the relationship between the injury and employment, and even the extent of harm. For a deeper walkthrough of how DBA claims move through the administrative system, see our step-by-step guide to the DBA claims process.
How Do Carriers Try to Rebut the Section 20(a) Presumption?
The carrier's rebuttal burden is specific: produce "substantial evidence" that the injury did not arise out of or in the course of employment. This is a production burden, not a persuasion burden. The carrier does not need to prove the injury was non-compensable. It needs to introduce enough credible evidence to call the presumption into question.
OALJ decisions in ClaimTrove's database reveal five primary rebuttal strategies carriers deploy. The most common is the independent medical examination. Carriers retain physicians who opine that the claimant's condition predated employment, was caused by non-work activities, or is unrelated to the claimed mechanism of injury. The ALJ then weighs the IME against treating physician testimony.
The second strategy targets the "course of employment" element directly. Carriers argue the claimant was on a personal errand, off-duty, or outside the zone of special danger when injured. In DBA cases overseas, this argument runs headlong into the "zone of special danger" doctrine, which holds that employees stationed in hazardous overseas locations face covered risks at virtually all times. Jurisdiction disputes in overseas settings add another layer of complexity. Our analysis of overseas injury location disputes covers that intersection in depth.
Third, carriers challenge the medical causation link. They present evidence that intervening events, pre-existing conditions, or non-occupational exposures caused the harm. Psychiatric injury claims draw this challenge frequently. Carriers argue that PTSD or anxiety stems from personal life stressors rather than combat-zone exposure.
Fourth, carriers contest the employment relationship itself, arguing the claimant was an independent contractor rather than an employee. This tactic appears less frequently in DBA cases because federal contracts almost always create the employment relationship through the prime-sub chain.
Fifth, some carriers raise procedural defenses: untimely notice, statute of limitations, or failure to pursue medical treatment. These do not directly rebut the 20(a) presumption but can defeat the claim on other grounds.
What Happens After the Carrier Produces Rebuttal Evidence?
Successful rebuttal does not kill the claim. This is a point many attorneys on both sides misunderstand. When the carrier produces substantial evidence sufficient to rebut the presumption, the presumption "drops out" of the case. The ALJ then weighs all the evidence as a whole, with the claimant bearing the ultimate burden of persuasion by a preponderance.
The BRB has described this as a "bursting bubble" approach. The presumption inflates the claimant's case until the carrier pops it with substantial evidence. Once popped, the presumption no longer tips the scales. But the underlying evidence the claimant introduced to invoke the presumption remains in the record and carries its natural probative weight.
In practice, this means the claimant's prima facie evidence often carries the day even after rebuttal. If a treating physician testified that work activities aggravated the condition, that testimony does not vanish when the carrier's IME doctor disagrees. The ALJ evaluates credibility, consistency, and the completeness of each medical opinion.
ClaimTrove data from OALJ decisions shows that ALJs frequently credit treating physicians over IME doctors, particularly when the treating physician had a longer and more detailed relationship with the claimant. The rationale is straightforward: the doctor who treated the patient over months or years typically has a better understanding of the condition than the doctor who examined the patient once for 45 minutes at the carrier's request. For a broader look at how ALJ reasoning shapes DBA outcomes, see our guide to what attorneys can learn from OALJ decisions.
The three-step framework, then, is: (1) claimant establishes prima facie case, (2) presumption attaches, (3) carrier rebuts or fails to rebut, and (4) if rebutted, ALJ weighs all evidence on the record. Claimant attorneys who build strong prima facie cases with detailed medical evidence create a floor that the carrier's rebuttal often cannot push below.
Why Does the Zone of Special Danger Doctrine Supercharge Section 20(a) in DBA Cases?
DBA claims differ from domestic Longshore claims in one critical respect: the zone of special danger. The Supreme Court established in O'Leary v. Brown-Pacific-Maxon (1951) that employees working in remote or hazardous overseas locations face employment-related risks that extend well beyond the physical worksite. Under this doctrine, injuries sustained during recreational activities, meals, sleep, or local travel can all fall within the scope of employment.
When combined with Section 20(a), the zone of special danger creates an extraordinarily claimant-friendly framework. The claimant invokes the presumption by showing an injury occurred while stationed overseas at a hazardous location. The carrier must then produce substantial evidence that the injury fell outside the zone of special danger, a zone that courts have interpreted to cover nearly every waking and sleeping moment of an overseas deployment.
Carriers struggle with this combination. Their most viable rebuttal is showing the claimant engaged in conduct so egregious or disconnected from the conditions of overseas employment that it broke the causal chain. Self-inflicted injuries, injuries during unauthorized personal travel far from the duty station, or injuries arising from purely personal disputes unrelated to employment conditions have succeeded in some cases.
But the bar is high. ALJs have found injuries compensable when claimants were injured playing sports on base, socializing at approved recreation facilities, and traveling between approved living quarters and the worksite. The overseas environment itself is the hazard. The presumption reinforces what the zone of special danger already suggests: that the default answer is compensability.
Understanding how these two doctrines interact is essential for DBA practitioners. The five landmark BRB decisions covered in our article on BRB decisions every DBA attorney should know include several that shaped this framework.
Which Types of DBA Claims Benefit Most from the Presumption?
Not all DBA claims invoke Section 20(a) equally. The presumption provides the most leverage in cases where the causal connection between work and injury is plausible but not immediately obvious. Three claim categories stand out.
Occupational disease claims. Hearing loss from generator noise, respiratory conditions from burn pit exposure, and repetitive stress injuries from manual labor overseas all involve gradual onset. The claimant cannot point to a single workplace incident. Section 20(a) bridges the gap by presuming the employment conditions caused the disease once the claimant shows exposure and a compatible diagnosis. Carriers must then produce evidence of alternative causation, which is difficult when the claimant was stationed in a controlled overseas environment.
Psychological injury claims. PTSD, anxiety, and depression arising from combat-zone deployments are increasingly common in DBA litigation. The presumption is critical because psychological causation is inherently harder to prove than a broken bone from a vehicle rollover. Claimant attorneys need a mental health professional to link the condition to employment stressors. Once that link is shown, the carrier must produce substantial evidence that non-work factors caused the condition, a difficult task when the claimant spent 12 months in Helmand Province. For a detailed breakdown of how these claims develop — including carrier identification problems that compound the causation analysis — see our guide to DBA PTSD and psychological injury claims for combat-zone contractors.
Aggravation claims. A claimant with a pre-existing back condition whose work duties overseas aggravated the condition can invoke the presumption. The carrier then bears the burden of showing the aggravation was not work-related. The BRB has consistently held that employers take employees as they find them. Pre-existing conditions do not defeat compensability when employment aggravates them.
The types of benefits available once compensability is established, from temporary total disability through permanent partial disability, are covered in our breakdown of LHWCA benefit types and calculation methods.
ClaimTrove indexes 5,022 OALJ decisions searchable by doctrine, claim type, and outcome. If you need to find how ALJs have applied the Section 20(a) presumption to a specific injury type or carrier defense, run an investigation on ClaimTrove to surface the relevant decisions in seconds rather than hours.
What Mistakes Do Claimant Attorneys Make When Relying on the Presumption?
The presumption is powerful, but it is not self-executing. Three recurring errors weaken claimant positions in OALJ proceedings.
Failing to establish the prima facie case properly. Some attorneys assume the presumption applies automatically to any DBA claim. It does not. The claimant must introduce some evidence, however minimal, connecting employment to the injury. A bare allegation without any medical opinion or factual support will not invoke the presumption. Even a brief treating physician note stating the work environment "could have contributed" to the condition is typically enough. Without it, the ALJ never reaches the burden-shifting stage.
Not preparing for the post-rebuttal phase. Attorneys who rely entirely on the presumption and fail to build a robust evidentiary record are vulnerable when the carrier produces a competent IME. Once the presumption drops out, the claimant must win on the merits. This means having detailed medical testimony, employment records, and witness statements ready for the weighing phase. The presumption should be a shield that buys time, not the entire defense.
Ignoring carrier identification issues. You cannot invoke the presumption against the wrong carrier. DBA carriers shift over time. Contractors change insurers between policy periods. The carrier on a 2018 policy may differ from the carrier covering a 2022 exposure. Filing against the wrong carrier wastes months and delays benefits. Identifying the correct carrier for the correct period is a prerequisite to any Section 20(a) strategy. ClaimTrove's investigation engine cross-references 18 federal data sources to trace the employer-to-carrier chain across fiscal years, resolving the temporal complexity that manual research often misses.
Getting the carrier right is the foundation. Everything else, including the presumption, builds on that foundation.
How Should You Structure a Section 20(a) Argument in Your Brief?
Effective Section 20(a) briefing follows the statutory framework step by step. ALJs are accustomed to this structure and expect it. Deviating invites confusion.
Open with the prima facie case. Identify the injury and the working condition or employment event that could have caused it. Cite the treating physician's opinion connecting the two. Keep this section factual and concise. The threshold is low, so do not over-argue it.
State that the presumption attaches. Cite the statute (33 U.S.C. Section 920(a)) and the applicable DBA incorporation provision (42 U.S.C. Section 1651(a)). Reference the BRB's articulation of the presumption standard from controlling decisions.
Challenge the carrier's rebuttal evidence. This is where most cases are won or lost. Attack the IME doctor's credentials, the completeness of their review, the time spent with the claimant, and any inconsistencies with the medical record. If the carrier argues the injury was outside the course of employment, invoke the zone of special danger doctrine and demonstrate that the claimant's activity fell within its scope.
Argue the weighing phase in the alternative. Even if the ALJ finds the carrier's evidence sufficient to rebut the presumption, argue that the claimant's evidence preponderates on the whole record. Emphasize the treating physician's longitudinal knowledge, the consistency of the claimant's account, and the inherent limitations of a one-time IME.
Close with the remedy. Connect compensability to the specific benefits sought. An ALJ who finds in the claimant's favor on compensability must then address the nature and extent of disability.