Linden, NJ – One child has died, and another is in critical condition after an apparent carbon monoxide poisoning incident in Linden Tuesday.

Firefighters were called to the scene on Passaic Avenue at 7:30 a.m. after reports of difficulty breathing.

Two children were found in distress in a bedroom, according to Linden Fire Chief Joseph Dooley. Along with their mother, 45, the two were taken to hospitals.

A 9-year-old boy was pronounced dead at Trinitas Hospital and his 10-year-old sister is in extremely critical condition at Newark Beth Israel Hospital.

City officials said it appears to be accidental carbon monoxide poisoning.

Firefighters found high levels of carbon monoxide in the bedroom where the children were found.

The carbon monoxide leak was possibly caused by improper venting of fumes from the furnace. The home was aired out.

There was also a carbon monoxide detector in the house but it appeared to be not working, according to the Linden Police Department.

An investigation is under way.

Linden School Superintendent Danny A. Robertozzi released a statement:

“Today, the Linden Public School District mourns the loss of a third grade student from School No. 4. According to the Linden Police Department, our student’s untimely death appears to be a tragic accident caused by carbon monoxide poisoning. The entire Linden Public School community is deeply saddened by this tragedy. Our most heartfelt sympathies and thoughts go out to the family and the entire School No. 4 community. There will be grief counselors and support assistance on hand for the duration of the week for students, staff, and families who may need help coping with this tragedy.”