A Continental Airline flight headed for Houston did an about-face this morning -- and made an emergency landing in San Antonio.

The 50-minute flight was halted after the pilot and flight attendant noticed a strong chemical odor.

The Boeing 7-37 was carrying 152-passengers - all of which were examined by medics immediately following the landing.

Four-people were treated for respiratory distress - one person was taken to the hospital.

No word yet on what caused the foul odor.