Laserfiche WebLink
The Agency decided on the five year frequency period after long consideration and <br />consultation with state officials. EPA staff determined that the requirement for a mechanical <br />integrity test at least every five years during operation of the well would provide satisfactory <br />assurance of continued well soundness and in addition would be reasonable from a cost <br />perspective. Moreover, the five-year review schedule facilitates Agency efforts to combine the <br />several permit programs under its charge. <br />A second protective feature of these regulations is the requirement for a tubing and <br />packer, fluid seal, or an alternative approved by the director for Class I wells. The Agency <br />applied this requirement to Class I wells due to the potentially corrosive nature associated with <br />Class I wastes. This requirement does not apply to municipal. wells injecting non-corrosive <br />fluids. The reproposal specified only tubing and packer or alternative. As a result of public <br />comment, the Agency included the use of a fluid seal in the final regulations. Fluid seals are <br />used extensively and have proved effective. Tubing and packer can best be described as a <br />removable liner device within a well which isolates the casing of the well from injected fluids. <br />By preventing this contact between casing and injected fluids, the possibility of movement of <br />contaminants through leaks in the casing is greatly diminished. For the same reason, tubing and <br />packer or equivalent also lessens the chances of corrosion of the casing. Tubing and packer <br />offers two further advantages. It isolates the annulus (between the tubing and casing) from the <br />injection zone, facilitating detection of any leaks in the tubing. It also allows for visual <br />inspection for deterioration of the tubing during routine maintenance." <br />The regulations make the use of tubing and packer or an acceptable substitute mandatory <br />for Class I well S,20 except for municipal wells injecting only non-corrosive wastes. EPA expects <br />that Class I wells will be injecting highly corrosive material more frequently than Class II or III <br />wells," hence, routine use of tubing and packer or an acceptable substitute becomes appropriate <br />(For Class II and III wells, the requirement to use tubing and packer is discretionary with the <br />Director because the inflexible use of the requirement for Class II and III wells would likely <br />interfere with production from many of these wells without any significant benefit to protecting <br />USDW).22 Even though a tubing and packer requirement is not mandatory for wells in Classes II <br />and IIt Directors should require its use when appropriate to prevent fluid migration into <br />underground sources of drinking water.) <br />When the use of a packer in Class I wells is inappropriate, the regulations allow for use of <br />alternative means to accomplish the'saime objective provided that the Director approves such <br />19 Subsurface Wastewater Injection, Chapter 7. <br />20 §146.12(c). <br />zl Report to Congress, Section XIII; Ground-Water Pollution, Part 2, Section II. <br />zz Subsurface Wastewater Injection, Chapter 7. <br />Page 10 of 20