ORLANDO, Fla. – The Occupational Safety and Health Administration is now investigating Universal's Volcano Bay after workers were sent to the hospital over the weekend.

• OSHA investigating incident at Universal's Volcano Bay
• Workers were sent to hospitals after electrical issue at the park
• Guests visiting Sunday complained of feeling "electric shocks"

On Sunday, the Orlando Fire Department responded to a medical call at the water park at about 4:44 p.m. The four workers, including lifeguards, were taken to hospitals as a precaution. They were released a short time after.

The park then closed early for the day.

In a statement released Sunday, Universal spokesman Tom Schroder said the incident was a "technical issue." However, guests visiting the park complained of feeling electrical shocks near one of the rides shortly after the park opened for the day.

On Wednesday evening, Universal released an updated statement about Sunday's incident, confirming the problem was indeed electrical.

"Our public statement used the phrase, 'technical issues,'" Schroder said in an email. "We wanted to fully understand what was happening and to what degree--and then fix it. We have worked with OUC, outside electrical contractors and our own experts--and we now know the problem is specifically electrical. We have spent the hours and days since Sunday testing and re-testing our electrical system across the entire park. And we have made repairs and modifications to our electrical system."

OSHA officials were at Volcano Bay on Wednesday, Universal said. OSHA hasn't shared any additional details about its investigation.

Some attractions at Volcano Bay remain closed while Universal continues with its testing, Schroder said.

"We believe this problem is resolved and that our park is safe," Schroder added.