Also known as: adequate warning · adequacy of warnings · warning adequacy · sufficient warning · warning sufficiency
Written by attorneys · grounded in primary & secondary sources — see below
A standard in tort law under which reasonable efforts to inform others of foreseeable risks prevent an otherwise dangerous act from constituting negligence. The determination turns on whether the warning conveyed the specific nature of the hidden danger to those likely to encounter it.
Vega Solar lent its portable inverter to Riley Renewables for a rooftop project. Vega knew the unit contained an internal arcing defect that could ignite a fire at full load yet described the equipment only as a bit temperamental. Electrician Mason suffered severe burns when the inverter caught fire. Mason's negligence claim against Vega proceeds because the vague comment failed to convey the concrete fire hazard.
Rose Cipollone smoked cigarettes for decades and later developed lung cancer. She sued the manufacturers alleging that the warnings on the packages were inadequate to alert smokers of the full health risks. The court examined whether the federal labeling requirements displaced state failure-to-warn claims.
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Diana Levine received an injection of Phenergan that caused severe tissue damage. She claimed the drug label failed to warn adequately against the intravenous-push method. Wyeth argued that FDA approval of the existing label preempted any state-law duty to strengthen the warning.
A patient suffered injury after taking a prescription drug whose risks were known to the manufacturer. The suit alleged that the manufacturer failed to provide adequate warnings of those risks. The court applied comment k principles to determine whether the warning satisfied the manufacturer's duty.
Patients taking generic metoclopramide developed tardive dyskinesia after prolonged use. They sued the generic manufacturers for failing to strengthen the warning on duration of therapy. The manufacturers contended that federal regulations prevented them from unilaterally altering the label.
Women whose mothers took DES during pregnancy later developed cancers. They sued multiple manufacturers without being able to identify the specific producer of the drug each mother received. The court considered whether the collective failure to provide adequate warnings supported liability under market-share principles.
A warning is adequate when it reasonably conveys the specific nature of the hidden danger to foreseeable users who would not otherwise appreciate the risk. Vague language that fails to identify the concrete hazard leaves the supplier exposed to liability.
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FDA approval does not by itself prove adequacy for state-law purposes. A plaintiff may still show that a stronger warning was possible and would have prevented the injury.
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When a manufacturer provides an adequate warning to the prescribing physician, the duty to warn the patient is generally satisfied because the physician acts as a learned intermediary who can assess the risk for the individual patient.
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…Levine’s injury resulted from an intravenous injection of Phenergan, and her claim that the drug’s label did not contain an adequate warning about that risk is the central issue in this case. Wyeth manufactures Phenergan, a drug that has been approved by the Food and Drug Administration (FDA) since 1955. The drug is used to…