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He was not the first person to get sick in the room. When Markowski was almost killed by a carbon monoxide leak at a hotel in Oklahoma, his lawyer sent him the fire department's report.

In the last two weeks, we have responded to this exact room number twice.

According to medical reports, Mr. Markowski was found unresponsive on the floor of his hotel room.

It is rare for incidents like Mr. Markowski to go beyond the local news. The deaths of three Americans at the Sandals Emerald Bay resort in the Bahamas in May generated hundreds of news stories and sparked conversations about carbon monoxide.

In the wake of the tragedy, Sandals decided to install carbon monoxide detectors in all of its Caribbean hotels. Most resorts and hotels around the world don't place detectors in guest rooms.

There is a debate about how to prevent carbon monoxide poisonings in hotels in the US. Though smoke alarms are usually required in American hotel rooms, no state or hotel brand requires in-room carbon monoxide detectors, which can be purchased for as little as $30. They want hotels to put them in every room. The lodging industry doesn't think that's necessary.

The frequencies of incidents necessitate change. In the past year, carbon monoxide leaks at six other U.S. hotels killed two people and injured at least 35 other guests and employees. Interviews with fire officials, front desk staff and local news reports show that most of the time there was no working detector.

Over the past two decades, at least 1,090 people have been injured by carbon monoxide leaks in US hotels. According to a study published in the journal Preventive Medicine Reports, these figures could be many times higher.

In 2012 the International Fire Code was updated to say that hotels should place carbon monoxide monitors in common areas or guest rooms. Interviews with key stakeholders show that the lodging industry successfully lobbied to remove that requirement.

The International Fire Code and other building codes require that carbon monoxide detectors be installed in rooms with fireplaces and near fuel-burning appliances. This only applies to newer hotels. Six states don't require detectors in hotels.

In the past four years, at least 10 carbon monoxide deaths in Brazil and Mexico have been dealt with by both Airbnb and VRBO, but they don't require hosts to install detectors near sleeping areas. In a study, public health researchers found that 58 percent of hosts didn't install the detectors.

ImageThe Sandals Emerald Bay resort recently had a carbon monoxide leak that killed three people and injured a fourth.
The Sandals Emerald Bay resort recently had a carbon monoxide leak that killed three people and injured a fourth. Credit...Dimitrios Kambouris/Getty Images for Sandals
The Sandals Emerald Bay resort recently had a carbon monoxide leak that killed three people and injured a fourth.

Kris Hauschildt, whose parents died from carbon monoxide poisoning in a hotel room in North Carolina, asked how many people need to die in order for it to matter to the industry. After an 11-year-old boy died in the same room, investigators discovered a leak from a pool heater.

Ms. Hauschildt's idea was to track the poisonings at hotels, something no entity had done before. The National Fire Protection Association, a nonprofit group that establishes safety codes that set some state policies, required detectors in both new hotels and old hotels.

Every one of the country's 5 million or so guest rooms would have to have detectors if the lodging industry had its way. Lobbyists for major hotel chains argue that proper maintenance and installation of detectors should prevent most poisonings.

A spokeswoman for the American Hotel & Lodging Association said in an email that warning devices such as CO alarms are a secondary defense against carbon monoxide in hotel guest rooms. There is no chance of an accidental carbon monoxide exposure due to the proper maintenance of fuel fired appliances.

ImageKris Hauschildt at her home in Kalama. Wash. She holds a photograph of her parents, who died of carbon monoxide poisoning while staying in a hotel in North Carolina.
Kris Hauschildt at her home in Kalama. Wash. She holds a photograph of her parents, who died of carbon monoxide poisoning while staying in a hotel in North Carolina. Credit...Kristina Barker for The New York Times
Kris Hauschildt at her home in Kalama. Wash. She holds a photograph of her parents, who died of carbon monoxide poisoning while staying in a hotel in North Carolina.

Since he became the general manager of a factory there, Mr. Markowski has traveled to the area almost every week. He chose the hotel because it is close to the factory.

He knew something was wrong when he couldn't sleep after he checked into Room 205. He dismissed the feeling of being tired the next day just as he dismissed the bad night. He couldn't deny that there was something wrong when he returned to Room 205.

He felt like he was drunk.

He went to the lobby to see if there was anything wrong with the room. The front desk clerk might not have known that two other guests had called for help. One of the guests had chest pain and the other was throwing up.

Two previous guests went to the hospital. The hospital let them go.

The signs of carbon monoxide poisoning can be missed by hotel staff and doctors. It's partly because the symptoms could be caused by so many things.

The co- founder of the National Carbon Monoxide Awareness Association said that they call it the great mimicker.

Diagnostic confusion was a factor in the case. The night before they were supposed to check out, two people died, one of which was a travel adviser who was one of the top sellers for Sandals. Donnis Chiarella, who was staying on the other side of the wall, went to a clinic, according to her son. The Phillipses and Ms. Chiarella were found unresponsive the next morning in their adjoining beachfront villas. All three died later that day. The sole survivor was Ms. Chiarella.

Patrick Morrison is the chief of field services for the International Association of Fire Fighters, the largest union of firefighters and paramedics in the US. The union supports the requirement of detectors in all sleeping quarters.

If you can't get out to fresh air, you'll be overcome by it. People die in their sleep due to that.

Mr. Markowski lay on the floor screaming when he came back to his room.

When a device burns a fuel, carbon monoxide is released. The most common causes of carbon monoxide poisoning in hotels are boilers and heating systems. Other sources of carbon monoxide leaks include gas dryers, fire places and portable generators.

Generators should not pose a danger if they are used in a safe location. The exhaust vent is where carbon monoxide exits. There are usually problems when the device malfunction or the vent breaks. Mr. Markowski had a bird's nest in the room that was plugged by the hot water tanks.

The gas can follow air currents through small holes and even a dry wall and end up far away from the original source of the leak. According to fire authorities, the gas entered Room 205 through holes and crevasses.

Similar to removing oxygen from the air, filling a room with carbon monoxide can do the same thing. When people breathe in carbon monoxide, it binding with hemoglobin in the blood, causing less oxygen to be transported to vital organs.

On the morning of March 16, the plant manager was told that his boss, Mr. Markowski, had failed to show up. They did not get a response.

Mr. Morgan found Mr. Markowski's rental car at the hotel. After persuading the woman at the front desk to let him in, he found his boss curled up on the floor.

He couldn't say anything. He wasn't sure where he was.

The fire fighters who responded to Mr. Morgan's call pulled out a carbon monoxide detector because it was their third call to Room 205 in a week. If people stay in the room for more than an hour or 400 p.m., the alarm will go off at a rate of 70 parts per million. The Fire Department reported that Mr. Markowski was in his room at 764 pm. The water heating room was open at 1,500p.m.

The percentage of red blood cells bound with carbon monoxide in Mr. Markowski's blood was checked by doctors at the hospital. 50 percent is almost always fatal, and people with heart disease or lung disease are more likely to die at 35 percent. According to medical reports, Mr. Markowski had a blood percentage of 37.2%. Doctors told him that he was lucky to be alive.

He said that he was in good shape and that may have helped him.

About 30 to 50% of people who are poisoned experience lasting effects, including cognitive issues and heart damage, according to Dr. Weaver.

Two exhaust flues were detached from the hot water tanks in Mr. Markowski's case. Mr. Markowski filed a lawsuit against the hotel owner and the company that licenses its name because there was no carbon monoxide alarm near the tanks.

When asked if the hotel was owned and operated by the owner, Hilton said that questions should be directed to the hotel's owner. Kalpesh was involved in active litigation so he couldn't say anything. The American Hotel & Lodging Association asked about carbon monoxide policies.

The International Fire Code encourages the installation of detectors near fuel burning devices.

The issue is not detectors, according to Thomas G. Daly, a consultant and former employee of the hotel chain. Human error is when equipment isn't maintained and there is a leak.

He said that requiring detectors in every room is expensive because it involves not only installing a detector but also testing and upkeep. It is the wrong place to put monitors since it is better to catch leaks at the source.

Others say that Mr. Markowski's case is indicative of a broken system where poisoning incidents often take multiple incidents before leaks are identified and people only survive because someone comes looking for them. They say that it should be on lawmakers and hotels.

The hotel built by Mr. Desai was built before detectors were required in hotels. They were required by the state to be near fuel burning devices. He didn't know about the requirement, but he didn't think hotels were aware of it. Only a small number of states have statutes that outline who is responsible for making sure hotels have detectors.

The emphasis on fuel burning devices is a red herring according to Gordon Johnson, a lawyer specializing in carbon monoxide cases. He said that the issue is not where the carbon dioxide is created, but where it escapes and can be multiple floors away from the source.

ImageAn array of portable carbon monoxide monitors, which range in cost from $20 to $200 and have different levels of sensitivity.
An array of portable carbon monoxide monitors, which range in cost from $20 to $200 and have different levels of sensitivity. Credit...Kristina Barker for The New York Times
An array of portable carbon monoxide monitors, which range in cost from $20 to $200 and have different levels of sensitivity.

The lodging industry's cost argument is offensive, according to a lawyer who was poisoned by a carbon monoxide leak in a Warren, Mich., hotel with her son. She and her son ended up in the emergency room after a plumbing mistake at a hotel. There was no detector at the hotel. Three years ago, a cleaning woman stumbled on two people who had passed out from a leak in another room.

The company that owns the hotel and the plumbing company that installed the water heating system are being sued by the mother of a boy who died from carbon monoxide poisoning.

The hotel is owned and operated by a single individual, according to the statement. Hotels built after 2009 are required to have carbon monoxide detectors. They didn't respond to calls or emails.

The hotel replaced the fire alarm in every guest room with a combination of fire alarm and carbon monoxide detectors.

During a deposition, a hotel manager who was not accused of any wrongdoing said that one of the alarms revealed that a new pool heating vent was releasing carbon monoxide into a guest's open window.

The manager said that it was detected.

They contributed research.