One officer on the site told CBC News that investigators have discovered barrels with labels saying they contained kerosene and airplane fuel.
It marks the fifth-straight day that police have been searching Millard's farm after the disappearance of Laura Babcock.
The Ontario Provincial Police's UCRT or urban search and rescue, chemical, biological, radiological, nuclear and explosive response team is working at the property. OPP Constable Marc Walsh says the UCRT specializes in presumptive testing of hazardous materials.
The officers have brought three large white trucks and three smaller trucks with trailers attached to the them.
Millard is charged with first-degree murder in the death of Ancaster's Tim Bosma. Mark Smich is also charged with first-degree murder in the case.