WEST, TX - APRIL 18: With smoke rising in the distance, a law enformcement officer runs a check point at the perimeter about half a mile from the West Fertilizer Company April 18, 2013 in West, Texas. A massive explosion at the fertilizer company injured more than 100 people and left damaged buildings for blocks in every direction. The death toll from the blast, which occured as firefighters were tackling a blaze, is as yet unknown. (Photo by Chip Somodevilla/Getty Images)
A spokeswoman says about 20 members of the Texas National Guard are on the scene of a Central Texas fertilizer plant explosion working to help first responders.
National Guard Bureau spokeswoman Rose Richeson says the group's a civil support team. Its members act like consultants to first responders.
The unit typically has mobile labs and can perform air monitoring while also assessing chemical and biological hazards at disasters.
Richeson says other Guard forces that do search and rescue missions are on alert.
Wednesday evening's fire and explosion killed between five and 15 people in the small town of West and injured about 160 others.