A sterilization technician at a northern Indiana hospital failed to properly disinfect surgical tools, possibly affecting more than 1,000 patients who underwent surgery at the facility in recent months, the hospital said this week.

In a recent letter to patients, officials with Goshen Hospital in Goshen, Ind., said that “one step in a multi-step cleaning process was not completed with certain surgical instruments in a limited number of cases,” according to a copy of the letter obtained by Fox 42. This means the patients may have been exposed to diseases such as hepatitis B, hepatitis C, and HIV, hospital officials said.

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“The surgical instruments in question were still treated with our usual chemical disinfection and machine sterilization processes which include a wide margin of safety; however, such instruments may or may not have been completely sterile,” the letter continues.

Patients who underwent surgery at Goshen Hospital between April 1 and September 30 may have been exposed, though the hospital noted the risk of infection is low. The situation was remedied “immediately” after officials became aware.

Free testing is now being offered to the 1,182 patients who were possibly exposed to the diseases, per the letter.

The hospital assured the risk of infection is "low."

“As with any patient safety concern, we rigorously investigated all aspects around the incident,” said  Daniel Nafziger, hospital chief medical officer, in a statement. “We have put strict policies and additional safety measures in place to ensure it does not happen again. We also want to express our concern for each of these patients.”

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One patient, Lori Deboard, told WSBT-TV that she's worried about her health despite the hospital's assurances that the risk of infection is minimal.

“I was mad … because when you tell somebody that they could be at risk for something like that (it) not only involves you, it involves your family, your significant other,” she said. “I have grandkids and kids.”

The Associated Press contributed to this report.