EPA OSC and START were dispatched to a 22 car train derailment in Santa Fe, Texas that occurred at approximately 0530 hours. According to news sources this morning, a 1 mile area was evacuated after it was determined that an unknown substance was leaking. BNSF now reports that the release was asphalt and flue dust. The evacuation was reduced at 0900 hours to a 1/4 mile radius. CTEH has been conducting air monitoring for BNSF for VOCs and LEL with no detections noted. In addition, air monitoring for particulate matter has detected nothing above background.