FDA’s April 30, 2026 warning letter to Zoll Medical found the Chelmsford, Massachusetts company had built its MRI-compatible 731 ventilator risk analysis on 27 complaints — while FDA inspectors, pulling from the same 2016-to-2024 window, counted 50. Zoll’s own internal evaluation had labeled the hazard “life-threatening,” then determined the likelihood of a hazardous event as “remote.”
The letter follows a Form 483 issued after a February-to-April 2025 inspection of Zoll’s Chelmsford facility, which produces defibrillators, ventilators, sensors, and electrodes. Under 21 CFR Part 820, FDA found the products adulterated: the methods, facilities, and controls at the plant aren’t in conformity with current good manufacturing practice requirements. The agency also flagged Zoll’s X Series defibrillators, where the risk analysis failed to assess visible corrosion spots on the One Step electrode used for defibrillation and ECG monitoring.
The medical device reporting failure is distinct. Zoll learned of a 731 ventilator malfunction near an MRI on June 20, 2024. FDA received the mandatory report on March 10, 2025. That’s 263 calendar days against a 30-day statutory window, which is why the agency also cited the company for misbranding.
I read the timeline carefully. The 731 was already part of a 2024 Class I recall alongside Philips and Baxter for missing MRI safety labeling. That recall should have triggered corrective action under 21 CFR 820.100. Zoll submitted multiple responses; the agency found it “cannot determine the adequacy” of each. Having a CAPA process and executing it are different things.
Response is due within 15 business days of April 30.
— Rebecca Lauren