Autopsies are planned for three people who died of causes that appear to be related to the weekend snow storm.

A man and his daughter were found dead today, the apparent result of carbon monoxide poisoning that resulted from the use of a generator, according to the Allegheny County Medical Examiner’s office. The father and daughter were using the generator for heat because of an electric outage at their home in McKeesport.

Also, the examiner’s office is investigating what could be a third weather-related death. A man was found dead in his North Side home Saturday night, not long after he had been shoveling a sidewalk at his sister’s nearby home.

The father and daughter were identified as George Mateyo, 60, and Joelle Mateya, 19.

Their bodies were found at 12:18 a.m. today at their home on Milburn Street by a friend who was concerned because he hadn’t heard from them Saturday.

An investigator with the examiner’s office said it appears the cause of death will be carbon monoxide poisoning caused by fumes from the generator they were using to heat their home in the wake of an electric outage.

According to the U.S. Environmental Protection Agency, carbon monoxide is a byproduct of combustion. Fumes are produced as the exhaust emission from the burning of such fuels as natural gas, wood, and coal. The less complete the burning, the more carbon monoxide is generated.

A fume that can’t be seen or smelled, carbon monoxide can be produced in deadly levels by malfunctioning machines or it can accumulate to a toxic level in areas that are not well ventilated, according to the EPA.

Meanwhile, the Medical Examiner’s investigator said a doctor will determine whether a 57-year-old man who was found dead Saturday evening at his North Side home died of a heart attack following snow shoveling. His last known activity was shoveling his sister’s sidewalk, the investigator said.