There are four reasons why hotel rooms abroad — particularly in the Caribbean, Mexico, and Central America — carry CO risks that American travelers do not anticipate.

Reason One: Most countries do not require CO detectors in hotel rooms.

The United States, Canada, and most of Europe have requirements for CO detectors in residential spaces. Many Caribbean and Latin American countries do not require detectors in hotel rooms or vacation rentals.

When detectors are present, they are often installed in hallways or common areas, not in individual rooms. CO from a malfunctioning appliance in a room can reach lethal concentrations long before reaching a hallway detector.

Reason Two: Gas appliance maintenance standards vary dramatically.

Many resorts use gas water heaters, gas dryers, gas stoves, and gas pool heaters. In jurisdictions with weak inspection requirements, these appliances are maintained until they break, not on preventive schedules.

A water heater with a corroded vent can leak CO for months before being discovered. In a hotel room, that's the room your family is sleeping in.

Reason Three: Generators run constantly during power outages.

In countries with unreliable power grids, resorts often run backup generators during frequent outages. Generator exhaust placement is supposed to follow strict safety standards. In practice, exhaust is often vented near room intakes, near pool decks, near outdoor dining areas.

I have personally measured CO levels above 80 PPM at outdoor dining tables at Caribbean resorts during generator operation.

Reason Four: Vacation rentals have zero oversight.

Airbnbs, Vrbos, and private vacation rentals operate with even less scrutiny than hotels. The host's CO detector — if present — is whatever they bought at the local hardware store. Often expired. Often the wrong type. Often nonfunctional.

When your family books a Caribbean vacation rental, you are trusting an unknown host's safety judgment with your family's lives.