However, the school district added it had no evidence that the data of its staff employed at the end of 2017-2018 school year were accessed.
The school district disclosed on Thursday the accidental release of its employees' personal info.
According to officials, the information was sent out in response to a routine request for an employee list. That info was embedded in a file, which Katy ISD said was destroyed upon discovery.
Credit monitoring agencies were also promptly notified, KISD added.
Despite the incident, the school district said it believed it to be a "very low security risk."
"Katy ISD has also taken steps to proactively protect its employees affected by this incident, including providing a year of credit monitoring services, at no cost, to all staff directly impacted the incident," officials said.