With the winter season just starting to take hold in Baja California, several carbon monoxide poisoning deaths have been recorded in Tijuana, Mexico this week — an ongoing problem as people try to keep warm in countries with no federal carbon monoxide detection regulations. Four people have died — including a five-year-old boy and an infant — from suspected carbon monoxide poisoning likely from water heaters, according to Tijuana’s director of civil protection José Luis Jiménez. “What we find are high concentrations of carbon monoxide particles, which happens to coincide with the water heaters that are installed inside the home,” Tijuana Fire Department director Rafael Carrillo told NBC 7’s sister station, Telemundo 20, in Spanish. Noticias En Español Tijuana Nov 20 Calentón eléctrico provoca incendio que dejó dos adultos, una niña y un perro sin vida Tijuana Nov 21 Solicitan ayuda para familia intoxicada con monóxido de carbono en Tijuana Informational campaigns were already underway to inform residents about the dangers that come with protecting themselves from the cold. But local leaders said they will work to reinforce their messaging in light of recent events. “We will continue with the campaigns because the weather we are going to have this winter is very cold, we do not want to have more deaths, the situation that has happened is regrettable. We are going to work on the preventive issue and perhaps there should be more aggressive campaigns,” Jiménez said. Carbon monoxide is known as the silent killer because it presents as an odorless, colorless gas that is deadly in highly concentrated levels. The U.S. Consumer Product Safety Commission recommends that every home have a Carbon Monoxide alarm but each state’s requirements vary. In Mexico, carbon monoxide alarms are also recommended but not required. The issue has grabbed attention in the U.S. in recent years after travelers died from carbon monoxide poisoning in Mexico and other countries that don’t have laws requiring detectors, including a couple who died in their hotel in June 2023 near Los Cabos. It’s not an issue unique to foreign countries, though. Carbon monoxide leaks at several U.S. hotels have led to deaths and injuries in the last few years, and the U.S. Centers for Disease Control and Prevention says that more than 400 people die from unintentional poisoning each year; thousands more are hospitalized. Travelers have been urged to take their own detectors with them to hotels. Tijuana fire officials say carbon monoxide alarms are not a preventative measure but rather a backup to safe appliances. The U.S. Environmental Protection Agency agrees. “The critical thing here is not that the water heaters are bad or of poor quality, the critical thing is that they are not installed by a professional and the other thing is that they are inside the home without any ventilation,” Carrillo said. On top of carbon monoxide alarms, Tijuana Fire recommends that residents keep their water heaters or boilers outside of their home. If it must be inside, ensure it is in a well-ventilated area. Never leave cars running in a garage and don’t use the stove to keep warm. Separately this week, Telemundo 20 reported two adults, a girl and a dog died in a fire likely caused by an electrical heater in Tijuana.