UNION CITY - Law enforcement officers want New Jersey residents to know the dangers of carbon monoxide.

The warning comes after several people were treated for carbon monoxide poisoning in Union City. Four residents in a home on Palisade Avenue and two police offers were hospitalized Tuesday night after becoming overcome by the fumes.

“The levels of carbon monoxide were extremely high at the time,” says Union City Police Chief Richard Molinar.

Chief Molinar says that people can become sick before they even know there is a problem.

“It’s colorless, odorless and you don’t know it’s there until unfortunately someone succumbs to the effects,” he says.

Last April, East Orange resident Octavia Campbell and her 7-year-old daughter Christiana were found dead in their Dodd Street home after exposure to the gas.

The chief says residents should make sure carbon monoxide detectors are installed in their homes. Most smoke detectors now include carbon monoxide detection, and many towns offer free carbon monoxide and smoke detectors to those who do not have them.

Landlords are required by law to provide them in multiple dwelling buildings. Detectors should be placed close to where people sleep so they will be woken up if the alarm goes off.

Experts warn residents to be careful using furnaces, space heaters and gas ovens during the winter months. Items such as these often give off carbon monoxide gas.