Hi, I would like to know if water-based drilling muds in petroleum exploration are considered dangerous waste.

Thank you very much

Presume hazardous unless specifically using one known to be non-hazardous, e.g., HYDRO-GUARD™ :
"No monitoring of discharge points: the HYDRO-GUARD system exceeds all EPA standards for discharge of waterbased fluid using the recommended product mix."
http://www.halliburton.com/ps/viewpg.aspx?navigation_id=242&product_id=MSE::1054653194897318

Thanks, kenvlach. I suppose first of all is a treatment of the muds.

While DrillerNick gave a good answer to the same question on the other thread as to if Drilling Muds are Hazardous, the answer I would give is sometimes they could be classified as Hazardous depending upon the fluid.  Drilling muds can not only have a wide range of additives used to give them desirable properties, but they can also pick up materials from formations encountered while drilling.  Water based drilling muds in the past have been known to have high levels of lead and chrome.  If you are trying to dispose of this material and need it classified as either hazardous or non-hazardous, the only way to stay out of trouble have it characterized.

A little more information as to the nature of your problem could yield better suggestions.