Carbon monoxide has no color, no smell and no taste, and it kills by a trick. It rides the same seat in the blood that oxygen rides, and it holds on about two hundred times harder. The body keeps breathing, the lungs keep working, and the blood goes around full and useless.
The gas. It is made whenever fuel burns with too little air: in the exhaust of cars and trucks and small engines, in stoves and lanterns and charcoal grills, in gas and oil furnaces, and in portable generators (CDC). Indoors it builds up, and people and animals breathe it without knowing. The Centers for Disease Control and Prevention counts more than four hundred Americans dead every year from unintentional carbon monoxide poisoning not linked to fires, more than a hundred thousand emergency room visits, and more than fourteen thousand hospitalizations. The federal product safety agency keeps its own count, more than two hundred carbon monoxide deaths a year tied to consumer products, and links more than a hundred of those to portable generators; it also notes that one portable generator makes as much carbon monoxide as hundreds of cars (CPSC).
The trick. Oxygen moves through the body on hemoglobin, the protein in the red blood cell. Carbon monoxide binds the same protein, and the medical literature puts its grip at about 220 times oxygen’s, two hundred to two hundred fifty by the usual range (StatPearls). Every hemoglobin molecule it takes is one that cannot carry oxygen, and it does a second harm on top: it changes the way the remaining hemoglobin releases what oxygen it has, so the tissues get less even from the molecules that are still working. The heart and the brain, the two organs that need the most oxygen, are the first to suffer; the occupational safety agency’s plain version is that the gas displaces oxygen in the blood and deprives the heart, brain and other vital organs of it, and that a large amount can overcome a person in minutes without warning (OSHA). The symptoms are the body starving for oxygen, which is why they look like something else: headache, dizziness, weakness, an upset stomach, vomiting, chest pain, confusion, a picture the CDC says is often described as flu-like (CDC). The clues a clinician is told to look for: no fever with the symptoms, a history of exposure, and more than one patient with the same complaints at the same time (CDC clinical guidance). People who are asleep or drunk can die before they ever have a symptom (CDC).
The monitor that lies. The small clip on the fingertip that reads oxygen saturation works by shining two colors of light through the blood and measuring what the hemoglobin absorbs. Hemoglobin carrying carbon monoxide absorbs that light almost the way hemoglobin carrying oxygen does, and the device counts it as oxygen. The CDC’s clinical guidance says it flatly: the conventional two-wavelength pulse oximeter is not accurate when carboxyhemoglobin is present (CDC); the standard bedside devices cannot distinguish carboxyhemoglobin from oxyhemoglobin, and the saturation they report cannot be relied upon (StatPearls). A poisoned patient can read a normal ninety-eight percent. The number that matters is the carboxyhemoglobin level, which takes a blood sample run through a CO-oximeter, or a fingertip pulse CO-oximeter built to read it (CDC), and it is a number that disappears on its own: on room air the body clears half of the carbon monoxide in a little over five hours, on pure oxygen in under ninety minutes, and in a hyperbaric chamber at three atmospheres in about twenty-three minutes (StatPearls). That is why the treatment is pure oxygen until the symptoms are gone, usually four or five hours, and the chamber for the worst poisonings and for pregnant women even when they are less severely poisoned (CDC). It is also why the first blood draw is evidence: a level taken after hours of breathing room air may already be less useful than the one that could have been taken at the door.
The injury that comes later. Carbon monoxide does not always finish on the day of the exposure. A patient who is treated and sent home can come back days or weeks later with trouble thinking, remembering, moving, or holding a mood, the delayed neurologic sequelae of the poisoning; the clinical review puts the share of admitted patients who develop them anywhere from about a quarter to nearly half, and says the patients left with lasting trouble thinking should have a neuropsychological evaluation one to two months after recovery (StatPearls). The CDC tells clinicians to warn every discharged patient of possible delayed neurological complications and to repeat the medical and neurological exam in two weeks (CDC). The injury that matters most in a case, in other words, may not be in the first chart at all.
The storm. Texas has learned this twice in twenty years. After the 2005 hurricanes, federal and state investigators traced twenty-seven poisoning incidents in Alabama and Texas, seventy-eight people sickened and ten dead, and all ten of the deaths were in Texas; a portable generator was behind twenty-five of the twenty-seven incidents, and in every fatal one the generator or a gas stove was inside a home or garage. The detail that should change how people think about the back porch: generators that had been placed outside were, on average, about three feet from the house, and placements as far as seven feet away still poisoned the people inside (CDC, MMWR). In the week of the February 2021 freeze, fire departments in Harris County alone answered 475 carbon monoxide calls (ABC13), and across the state at least eleven people died and more than fourteen hundred sought emergency or urgent care for the poisoning, children making up forty-two percent of the cases, in what one physician who has studied the gas for thirty years called the biggest epidemic of carbon monoxide poisoning in recent history (NBC News, with The Texas Tribune and ProPublica). The rule the CDC repeats is distance: a generator runs outdoors only, more than twenty feet from any window, door or vent, never in a house or a garage even with the doors open, and a car never runs in an attached garage even with the door up (CDC).
What the law asks. The gas is quiet, so the law looks at the people around the machine. The one who made it: federal rules have required a DANGER label on every portable generator manufactured or imported since May 2007 (16 CFR Part 1407), and a product that poisons the people it was sold to with a warning they were never given, or a design that let it happen, is a question for the product liability chapter. The one who rented the house: a Texas landlord must make a diligent effort to repair or remedy a condition that materially affects the physical health or safety of an ordinary tenant once the tenant gives notice and is current on the rent (Property Code Section 92.052), and a furnace or water heater that puts the gas into the rooms is that condition. The one who invited the guest in: a hotel owes its guest the care Invitee describes, against a danger it knew of or should have found. The one who ran the engine at work: the occupational safety standard caps exposure at fifty parts per million averaged over an eight-hour shift, and the agency’s own guidance tells employers to ventilate, to keep gasoline engines out of poorly ventilated spaces, and to give workers monitors with alarms where the gas may be present (OSHA). And the alarm itself: in 2021 Texas was one of six states with no statewide requirement for a carbon monoxide alarm in a home, having left the rules to its cities and counties, where they vary widely (NBC News), so the absence of one is rarely a code violation and always a fact.
The move. The appliance as it was, before anyone fixes it or hauls it away: the generator and where it sat, the heater, the furnace, the water heater and its vent, the car and the garage. The labels it carried and the manual it came with. The first carboxyhemoglobin level and the time it was drawn, because the number falls by half every five hours or so on air. The detector, or the place on the wall where there was none. The weather, the outage, and the hours. And the follow-up visits at two weeks and two months, because the part of this injury that lasts is the part the first chart did not see.
Carbon monoxide takes oxygen’s seat and gives it back only slowly. The body cannot smell it, the monitor cannot see it, and the only protection is distance, a working alarm, and the people who owed both.
The science: McMahon and Launico, Carbon Monoxide Toxicity, StatPearls (NCBI Bookshelf, updated April 2025) (hemoglobin combines with carbon monoxide 220 times more avidly than with oxygen; the leftward shift of the dissociation curve; standard pulse oximetry cannot distinguish carboxyhemoglobin from oxyhemoglobin; delayed neurologic sequelae in 23 to 47 percent of admitted patients; half-life about 320 minutes on room air, under 90 minutes on 100 percent oxygen, about 23 minutes at 3 atmospheres); CDC, Clinical Guidance for Carbon Monoxide Poisoning (the conventional two-wavelength pulse oximeter is not accurate when carboxyhemoglobin is present; no fever, a history of exposure and multiple patients as clues; 100 percent oxygen until symptom-free, usually 4 to 5 hours; hyperbaric oxygen for levels above 25 to 30 percent and for pregnant women; warn of delayed neurological complications and re-examine at 2 weeks); CDC, About Carbon Monoxide Poisoning (odorless, colorless; the sources; the symptoms; more than 400 deaths, 100,000 emergency visits and 14,000 hospitalizations a year; generators more than 20 feet from windows, doors and vents); OSHA, Carbon Monoxide Poisoning fact sheet (the mechanism in plain terms; the 50 ppm permissible exposure limit averaged over 8 hours; the agency’s guidance for employers). The storms: CDC, Carbon Monoxide Poisonings After Two Major Hurricanes, Alabama and Texas, August to October 2005, MMWR 55(9):236 (March 10, 2006) (27 incidents, 78 nonfatal cases, 10 deaths, all in Texas; a generator in 25 of 27 incidents; outdoor generators an average of 3.2 feet from the home, range 1 to 7 feet; every fatal incident with the generator or stove inside a home or garage); ABC13, Feb. 24, 2021 (475 carbon monoxide calls to Harris County fire departments in one week); NBC News, with The Texas Tribune and ProPublica, April 2021 (at least 11 deaths and more than 1,400 people who sought emergency or urgent care for the poisoning during the outage; children 42 percent of cases; Texas one of six states with no statewide requirement for carbon monoxide alarms in homes, the rules left to local governments); CPSC, Carbon Monoxide Information Center (more than 200 deaths a year from carbon monoxide associated with consumer products, more than 100 of them linked to portable generators; one generator makes as much carbon monoxide as hundreds of cars). The law: 16 CFR Part 1407 (the DANGER label required on portable generators manufactured or imported on or after May 14, 2007); Tex. Prop. Code § 92.052. General information, not legal advice.
