The violations occurred when Halliburton stored, treated and transported waste hydrochloric acid without obtaining proper DEP permits.

During the 12-year period Halliburton transported acidic waste that had originated from various gas wellsites without identifying the waste as "hazardous waste".

It also failed to keep proper hazardous waste trucking records and did not use a licensed hazardous waste transporter.

In addition, the company sent the hazardous waste to an unauthorised treatment and disposal operation.

The DEP said while there had been no evidence Halliburton's handling of the hazardous waste caused any harm to the public or the environment, the company violated state regulations governing the handling, storage, transport and disposal of hazardous waste on hundreds of occasions.

"Our regulations are in place to protect the health and safety of our residents and to preserve our environmental resources," DEP secretary Chris Abruzzo said.

"Halliburton's repeated disregard of these regulations is unacceptable."