You just got a letter that says your blood or urine will be tested after a chemical spill at work, near a farm operation, or along a trucking route like US-85. Biomonitoring is the measurement of chemicals, their breakdown products, or other exposure markers inside the human body. Instead of testing air, soil, or water alone, it checks what actually entered a person's system. Common samples include blood, urine, hair, or breath, depending on the substance involved.

That matters because exposure cases often turn on proof. Biomonitoring can help show whether someone was exposed to pesticides, solvents, heavy metals, fuel vapors, or other toxic substances, and sometimes whether the exposure level was recent, repeated, or unusually high. It can also cut the other way: a low or negative result may be used by an insurer or defendant to challenge causation, damages, or even whether an exposure happened at all. Test timing matters. Some chemicals leave the body quickly, so delayed testing can weaken a case.

In an injury claim, biomonitoring is usually one piece of the puzzle, not the whole case. Medical records, symptom history, workplace records, and environmental testing still matter. In North Dakota, claims tied to oilfield traffic, agriculture, or industrial work may involve state agencies such as the North Dakota Department of Environmental Quality, but no single North Dakota statute makes biomonitoring mandatory in every toxic exposure claim.