Burden of Proof

The burden of proof is the responsibility a party in a lawsuit has to prove the facts they are claiming. In an asbestos case, the patient (the plaintiff) generally must show that they were exposed to a defendant's asbestos product and that this exposure caused or contributed to their disease. In civil cases, this proof only needs to be "more likely than not", far less than the "beyond a reasonable doubt" standard used in criminal cases.

Origin

The phrase comes from the Latin onus probandi ("burden of proving"), a principle rooted in Roman law and carried into English common law. It has been a cornerstone of Anglo-American civil procedure for centuries and governs which party must come forward with evidence on each disputed issue.

Significance in Asbestos Context

For a patient with mesothelioma, lung cancer, or asbestosis, the burden of proof shapes what their legal team must gather and present: a work and exposure history, product identification (which companies' asbestos-containing products you were around), medical records confirming the diagnosis, and expert testimony connecting the exposure to the disease. Because asbestos diseases can take 20–50 years to appear, proving exposure that happened decades ago is often the hardest part, which is why old pay stubs, union records, military service records, co-worker statements, and even family memories of dusty clothes can become critical evidence. The burden stays with the plaintiff throughout, though once you present credible evidence, the defendant must respond. In civil asbestos cases the standard is "preponderance of the evidence" (more than 50% likely), not the much higher criminal standard, which is an important point patients and families often misunderstand.

Example Sentence

Her attorney explained that to meet the burden of proof, they would need to document every shipyard where she worked alongside her husband and identify which insulation products were used there.

Related Terms

Preponderance of Evidence, Causation, Product Identification, Substantial Factor Test, Standard of Proof, Expert Testimony

Notes

• Start writing down every job, military assignment, home renovation, and second-hand exposure (like a spouse's dusty work clothes) you can remember, dates, locations, employers, and specific products if you recall them. This memory work is foundational to meeting the burden of proof.
• Gather and preserve Social Security earnings records, union membership records, DD-214 military discharge papers, tax records, and old photographs of worksites; your legal team will use these to corroborate exposure.
• Ask your treating physicians to clearly document the asbestos-related diagnosis and any occupational history they took. This medical record language matters when proving causation.
• Burden of proof is not the same as standard of proof: the burden says who must prove something; the standard says how convincingly. In asbestos civil cases, the standard is "more likely than not."