(CNN) -- At least 50 vehicles were involved in a wreck that hurt dozens of people and closed part of a highway in southeastern Texas on Thursday, authorities said. At least 54 people were taken to various medical centers, including four who were in critical condition, said Deputy Rod Carroll of the Jefferson County Sheriff's Department. Two vehicles caught fire, and several had heavy damage, he said. "We are very fortunate not to have any fatalities," Carroll added. "Not in my 23 years working have I seen anything like that." Poor visibility stemming from a mixture of fog and smoke probably caused the wreck, authorities said. Wildfires produced the smoke. A portion of state Highway 73, about 5 miles west of Port Arthur, was closed in both directions.
NEW: 54 people are injured in a vehicle pileup on a Texas highway . NEW: Four people remain in critical condition . NEW: Texas state Highway 73 is shut down after a pileup involving at least 50 vehicles . It was likely caused by poor visibility stemming from a mixture of smoke and fog .