KINGFISHER COUNTY, Oklahoma - State regulators filed a contempt charge against an oil and gas company accused in a fracking-related chemical spill, one that officials said is likely the largest spill of its kind in state history.

State records show a tank holding 480 barrels of hydrochloric acid spilled at an oil and gas well site in Hennessey late last month; that's more than 15,000 gallons.

Environmental cleanup crews are still digging up soil there, trying to find out how deep the acid leached into the ground.

According to the contempt charge, Blake Production Company could face fines of up to $5,000 for each day it's polluted the site.