State Health Officials have now determined what caused three Iowa Falls Kwik Star Convenience Store employees to become seriously ill while at work on Tuesday.

According to John McHugh, Director of Corporate Communications for Kwik Star Incorporated, the problem was caused by oven cleaner that was not completely cleaned up before the store’s oven was used again.

The affected employees were sent to the hospital when proper  cleaning procedures were not followed and the oven cleaner vaporized.  All employees were reported as having returned to normal health status as of Wednesday.

Kwik Star was evacuated and the store was temporarily shut down after the incident occurred on Tuesday.

The store was reopened to the public again on Wednesday.

Store officials were initially concerned the problem may have been caused by sewer gas venting through the store.  In October of 2019, 14 employees were taken to the emergency room over a two day period due to a sewer gas leak that originated inside the store.