When the power went out across New Jersey, Michigan, and Pennsylvania on July 4 — cutting electricity to 1.3 million customers at peak — the public conversation focused on air conditioning. [1] For approximately 3 million Americans who depend on powered home medical equipment, the loss was categorically different. They did not lose a cooling appliance. They lost a ventilator, an oxygen concentrator, a nebulizer, or a refrigerator keeping insulin stable.

This paper's July 5 edition framed the 600,000-plus customer outage as a live shelter and medical-device test with the emergency still in progress. Today, as the outage resolves and the dome tracks west, the clinical consequences of the past 48 hours are becoming legible. The question is how many people in the medically vulnerable population — a number CDC estimates at roughly 3 million nationwide — faced the simultaneous loss of powered medical equipment and dangerous ambient heat, and what happened to them.

The convergence is precisely the scenario the CDC's heat-and-medications clinical guidance addresses. [2] That document, available to clinicians and updated regularly, identifies the patients most likely to decompensate in a heat-plus-outage event: those on oxygen concentrators, ventilators, dialysis equipment, and refrigerated insulin. What the guidance does not do — and what has not happened during this heat wave — is broadcast this list to the public in terms that would move a diabetic neighbor to check on the person three doors down. [2]

The biochemistry is not complicated. Insulin stored above 77 degrees Fahrenheit begins to degrade in hours. [1] Most insulin products specify that opened vials in use can tolerate room temperature for up to 28 days, but that threshold assumes a room temperature of 77 degrees or below — not the 85 or 90 degrees that an unair-conditioned apartment on the fourth floor of a brick building reaches by afternoon in a heat dome. A patient who lost power at 10 p.m. on July 4 faced a gradual but measurable degradation of their insulin supply through July 5. If they did not have ice, a cooler, or a way to reach a pharmacy, the medication they injected on July 6 may have been partially ineffective. [2]

For ventilator-dependent patients, the calculation is more immediate. Home ventilators typically have internal battery backups rated for 2 to 8 hours depending on the device. A 12-hour outage, or a 36-hour outage as some customers in New Jersey experienced, exceeds that backup window entirely. [3] The clinical pathway at that point is hospital transfer — which requires that someone know the patient is in distress, that transportation is available, and that the receiving hospital has capacity. During a heat dome, all three of those variables are under simultaneous pressure. Emergency departments in the region are already running above seasonal volume. [3]

Utility companies maintain Life-Support Equipment (LSE) programs that flag residential accounts with registered medical-priority users. These programs exist to prioritize restoration and, in some cases, to proactively notify LSE customers before planned outages. [1] The July 4 outage was not planned — it resulted from storm-related infrastructure failures — and the notification systems are not designed for simultaneous mass events. What is not known, and what no utility has disclosed as of publication, is how many LSE-registered customers in the affected territory lost power, for how long, and what outreach occurred. That number is the audit record this event demands.

The 3 million figure is a CDC national estimate based on home health care utilization data and durable medical equipment claims. [2] It is not a real-time registry. No utility, no health department, and no federal agency maintains a live list of residential medical-equipment users sorted by address and equipment type. This gap is known, has been flagged by disability-rights organizations for years, and has not been closed by federal policy. The July 4 outage will not close it either, unless someone with authority over utility emergency protocols decides to require LSE registration and activation as a condition of serving customers.

What the 48-hour window between outage onset and power restoration produced in terms of hospitalization, medication failure, and death among home-medical-device users in New Jersey, Michigan, and Pennsylvania is not yet in the public record. No health department has reported an aggregate count. No utility has disclosed LSE-program activation data. The individual cases — the ventilator patient transported by family to a hospital that had to locate a generator, the insulin-dependent diabetic who rationed doses through the heat — exist in emergency department records, in ambulance logs, and in the memories of family members who improvised solutions in the dark. [3]

They should be in a report. The population at the intersection of powered medical equipment, extreme heat, and utility outage is small enough to count and large enough to constitute a systematic vulnerability. The next heat dome will come. The LSE registry gap will still be there.

-- NORA WHITFIELD, Chicago