A school bus driver was drunk, with a blood alcohol content three times the legal limit, when she dropped students off at the Irving A. Robbins Middle School in Farmington on Wednesday morning, according to police.

M and J school bus driver Tammy Costello, 44, of Bristol, was arrested at school this morning after an officer driving behind her noticed the bus tires swerve off the pavement, according to police.

"He greeted students as they were getting off the bus, and a couple of them made reference to the potential that the driver may have hit a curb or two along the way," said Farmington police spokesman Lt. Colin Ryan.

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She was arrested and charged with driving under the influence, failure to drive right, and 20 counts of risk of injury to a minor – one for each of the students on board.

NBC Connecticut tried to contact Costello at her Bristol home, but there was no answer.

Farmington Supt. Kathleen Greider has sent a letter to parents saying every child who was on the bus was brought to the nurse to be checked for injuries and any other concerns.

"All students returned to class after a thorough assessment and parents were contacted. Please be assured that the safety of our students – your children – is our highest priority, and we take that responsibility very seriously," Greider said in the letter.

She also provided parents with a letter from the bus company.

"The M and J Bus Company is appalled at the incident that occurred this morning involving one of our bus drivers. We are committed to working closely with the Farmington Police Department to conduct a thorough investigation of this incident. Please know that thorough background checks of all employees are conducted by the Department of Motor Vehicles before employees are allowed to transport students," the statement says.

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The statement says M and J Bus Company conducts alcohol and drug testing when they hire employees, who are also subject to "rigorous random alcohol and drug testing."

M and J has suspended Costello pending an investigation.

"We hold our employees to the highest expectations and safety is our number one priority. We apologize to the Farmington community for this incident as we are a long-standing Farmington company and we are deeply committed to the safety of ALL Farmington students," the statement from M and J says.



Costello was released on a $25,000 non-surety bond and is scheduled to appear in Hartford Superior Court on Sept. 2.