Assistant District Attorney Anna Ferguson said 41-year-old Kurt Schoemig was charged Monday with two counts of involuntary manslaughter.
She said in a statement he "played a substantial factor" in causing the deaths of 69-year-old Albert Senzatimore of San Jose and 57-year-old Gary Trovinger of Los Gatos at Trovinger's home in Tahoe Donner in October.
Ferguson said Schoemig, president of Cedar Ridge Builders, didn't have the necessary permit for work done last year.
Police say an employee cut a furnace exhaust pipe, but the project wasn't completed, leaving the pipe to vent into the home when the heater started.
The Carmichael man accused of trying to kill his two children back in 2015 is set to be sentenced next month, after pleading guilty to the crimes on Thursday.
The survivors of crime victims spoke out Thursday in Stockton, coming together to tell their stories and honor their loved ones.
Update 11/14/2016, 6:50 p.m.: A Stanislaus County Sheriff Deputy was shot and killed yesterday while checking out a suspicious vehicle near Hughson.
A memorial continues to grow for a Marysville boxing trainer who was shot to death outside of his gym and in front of his eight-year-old son Wednesday.