"The presence of cocaine at a given blood concentration cannot usually be associated with a degree of impairment or a specific effect for a given individual without additional information," the NHTS report stated.
No other intoxicants were found in Pham's blood, according to the Orange County coroner.
Pham's family did not return a call for comment Thursday.
Pham, of Fountain Valley, was to get a notice saying he would be laid off in six months once Costa Mesa found an outside company to replace him as part of a broad austerity program.
Some employees have suggested Pham chose to commit suicide at that time and place — the eastside of City Hall where city leaders' cars are parked — to send a message on behalf of city workers.
His suicide, and the action of city leaders afterward, stoked anger among other workers and critics of the City Council. It was at a memorial for Pham that night and the next that residents began discussing uniting against the council and ultimately created Repair Costa Mesa, an advocacy group.
As mourning turned to anger in the weeks after Pham's death, many in the community took aim at Mayor Gary Monahan. In the hours after Pham's death, Monahan chose to remain working at his bar, Skosh Monahan's, for St. Patrick's Day — his busiest day of the year.
Monahan said at the time that because so many blamed the council for Pham's actions, his presence at City Hall while employees mourned would have only added fuel to the fire. He later apologized and pledged to do better in the future.
The Orange County Employees Assn. took Monahan's inaction and ran with it. The organization put money behind the Repair Costa Mesa name and turned it into a media campaign attacking him and the council, with many expecting an eventual recall effort.
OCEA represents about 200 Costa Mesa employees affected by the layoffs.
"Huy Pham was a dedicated worker who was under a great deal of stress," OCEA said in a news release. "We stand with his family during this time of tragedy. His coworkers and family loved him dearly, and they are in our prayers."
Some residents who first discussed what they could do to stop the city's direction at that memorial and later in their living rooms have since distanced themselves from Repair Costa Mesa and now call themselves the Costa Mesa Coalition.