(a) Waste analysis plan. All material injected into or produced from the cavern shall be sampled and analyzed in accordance with the approved written waste analysis plan required by 40 Code of Federal Regulations §146.68(a).
(b) Pressure gauges. Pressure gauges shall be installed and maintained in proper operating conditions at all times on both tubing strings and on the annulus between the outer tubing and long string casing/liner.
(c) Continuous recording devices. Continuous recording devices shall be installed and used, and maintained in proper operating condition at all times to record tubing string pressures, injection flow rates (by volume or mass), injection waste temperatures, injection waste density, volume and composition of displaced fluids and gases, injection volumes, tubing-long string casing annulus pressure, volume of annulus contents, and any other data specified by the permit. The composition of emplaced and displaced gases will be continuously recorded and monitored for change in composition. When a change in composition is detected a sample will be taken to establish the chemical composition of the displaced gases. The instruments shall be housed in weatherproof enclosures. The owner or operator shall also install and use:
  (1) automatic alarm and automatic shutoff systems, designed to sound and shut-in the well when pressures and flow rates or other parameters approved by the executive director exceed a range and/or gradient specified in the permit; or
  (2) automatic alarms designed to sound when the pressures, flow rates, or other parameters approved by the executive director exceed a rate and/or gradient specified in the permit, in cases where the owner or operator certifies that a trained operator will be on location and able to immediately respond to alarms at all times when the well is operating.
(d) Testing and calibration of monitoring instruments. All gauges, and pressure sensing and recording devices shall be tested and calibrated quarterly.
(e) Well mechanical integrity. The owner or operator shall maintain mechanical integrity of the injection well at all times that the well is in service. Mechanical integrity of the well must be demonstrated:
  (1) within 12-month intervals, or within extended intervals not to exceed 15 months upon approval of the executive director, during the operating life of the well;
  (2) by a temperature log, noise log, or other approved log required by the executive director at least once every five years to test for fluid movement along the borehole; and
  (3) a casing inspection, casing evaluation, or other approved log may be required by the executive director to determine the condition of the casing.
(f) Cavern integrity. The owner or operator must maintain cavern integrity at all times. The integrity of the cavern must be demonstrated within 12-month intervals, or within extended intervals not to exceed 15 months upon approval of the executive director, by:
  (1) pressure tests that determine if pressure interference or fluid flow exists between other caverns or formations; and
  (2) a sonar test, or other test approved by the executive director, to determine the geometric shape of the unfilled cavern.
(g) Corrosion monitoring.
  (1) Corrosion monitoring of well materials shall be conducted quarterly. Test materials shall be the same as those used in the injection tubing, packer, and long string casing, and will be continuously exposed to the waste with the exception of when the well is taken out of service.
  (2) Corrosion monitoring may be waived by the executive director if the injection well owner or operator satisfactorily demonstrates, prior to authorization to conduct injection operations, that the waste will not be corrosive to the well materials with which the waste is expected to come into contact throughout the life of the well. The demonstration shall include a description of the methodology used to make that determination.
(h) Ambient monitoring.
  (1) The executive director shall require the owner or operator to develop an ambient monitoring program, based on a site-specific assessment of the potential for waste and/or fluid movement from the well or injection zone and subsidence due to groundwater withdrawal or salt movement.
  (2) The executive director shall require subsidence and groundwater quality monitoring over the area of review, and any other type of ambient necessary to comply with §331.162 of this title (relating to Performance Standard).
  (3) Any monitor wells within the area of review selected for the observation of water quality, subsidence, formation pressure, or any other parameter, shall be monitored at an accuracy, frequency, and density sufficient to protect underground sources of drinking water, and fresh or surface water.
(i) Hydrogeologic compatibility determination. The owner or operator shall submit information demonstrating to the satisfaction of the executive director that the waste stream and its anticipated reaction products will not alter the permeability, thickness, or other relevant characteristics of the salt cavern confining or salt cavern injection zones such that they would no longer meet the requirements specified in §331.121 of this title (relating to Class I Wells).
(j) Other monitoring and testing. Any other monitoring and testing requirements, including determination of composition and volume of leachate, shall be specified as permit conditions.
(k) Notification of scheduled logging and testing. The executive director or his designated representative shall have the opportunity to witness all logging and testing. The owner or operator shall submit a written schedule of such activities to the executive director at least seven days prior to conducting tests.

Source Note: The provisions of this §331.166 adopted to be effective June 22, 1992, 17 TexReg 4097; amended to be effective November 23, 2000, 25 TexReg 11433