Authorities have said that a Utah exterminator faces charges of negligent homicide for allegedly spraying a toxic substance implicated in the deaths of two children.

The Salt Lake Tribune has reported that Coleman Nocks, the employee who used Fumitoxin on Feb. 5 to exterminate field mice at the Layton, Utah, home of Nathan and Brenda Toone, will be arraigned June 8 in Second District Court on two counts of negligent homicide for the alleged misapplication of the pesticide resulting in the February deaths of the Toone's children, Rebecca, 4, and 15-month-old sister, Rachel.

State records have indicated that this is the seventh time in 10 months Bugman Pest and Lawn allegedly applied too much Fumitoxin and the sixth time it used the poison too close to northern Utah homes, the newspaper said on Saturday.

The Tribune also reported that the alleged misapplications pertain to more than 3,500 instances of the Bountiful company and its workers breaking pesticide laws between April 2009 and February this year.

The newspaper also said that an attorney for Bugman Pest and Lawn declined comment, as did Utah's pesticide office.

Bugman owner Ray Wilson did not return phone calls.

"These materials are regulated for a reason. People go through training and are certified (to use them) for a reason," said Assistant Layton City Attorney Steve Garside, whose office filed the criminal charges against Nocks last month. (With Inputs from Agencies)