June 16 (UPI) -- The New York City Police Department ruled Tuesday that "no criminality" was involved in an incident that resulted in three officers being hospitalized after drinking milkshakes that a police union claimed were contaminated with a "toxic substance" at a fast-food restaurant in lower Manhattan.
The officers were eating a meal at a Shake Shack restaurant on Broadway and Fulton Street when "a toxic substance, believed to be bleach" was discovered in their drinks, the NYC Police Benevolent Association union said in a statement warning its members to be on alert.
"When NYC police officers cannot even take meal without coming under attack, it is clear that environment in which we work has deteriorated to a critical level," the union said in the statement. "We cannot afford to let our guard down for even a moment."
The union said the sickened officers are expected to recover.
The NYPD launched an investigation into the incident and determined there was no cause for charges, said Chief Rodney Harrison early Tuesday without further explanation.
"After a thorough investigation by the NYPD's Manhattan South investigators, it has been determined that there was no criminality by Shake Shack's employees," he tweeted.
A department spokesperson said the beverages were purchased at around 8:30 p.m.
The burger chain Shake Shack said it was "horrified" to learn of the incident and was working with police in their investigation.
We are horrified by the reports of police officers injured at our 200 Broadway Shack in Manhattan. We are working with the police in their investigation right now.— SHAKE SHACK (@shakeshack) June 16, 2020
The incident comes amid heightened scrutiny of police throughout the nation, including New York City, as protesters have taken to the streets demanding police reforms and equality following the police-involved killing of George Floyd late last month.
The union said the officers had been assigned to a protest detail in lower Manhattan, and advised its members to inspect any food they purchase while on duty.
"Whenever possible, take meal in groups of two or more, and remain vigilant for the duration of the meal period," it said.
A second union, the Detectives' Endowment Association, said the officers were "intentionally poisoned," urging police officers not to buy any food from unknown locations.
"Police in New York City and across the country are under attack by vicious criminals who dislike us simply because of the uniform we wear," the union said in a statement. "We MUST be more vigilant than ever."