Applicability. The requirements of this regulation apply to owners and operators of existing hazardous waste tank systems that do not have secondary containment meeting the requirements of Regulation .10-4 of this chapter. For each existing tank system that does not have secondary containment meeting the requirements of Regulation .10-4 of this chapter, the owner or operator shall: Develop, and keep on file at the facility, a written assessment of whether the tank system: Is leaking or otherwise unfit for use; Will collapse, rupture, or fail based on an analysis of the tank system design, structural strength, and compatibility with the waste or wastes to be stored or treated; Have the assessment required by §B(1) of this regulation reviewed and certified by an independent, qualified registered professional engineer, in accordance with COMAR 26.13.07.03D; Assure that the assessment required by §B(1) of this regulation considers, at a minimum, the following: Design standards, if available, according to which the tank and ancillary equipment were constructed; Hazardous characteristics of the waste or wastes that have been and will be handled; Existing corrosion protection measures; Documented age of the tank system, if available, or, if not, an estimate of the age; Results of a leak test, internal inspection, or other tank integrity examination such that: For nonenterable underground tanks, the assessment includes a leak test that is capable of taking into account the effects of temperature variations, tank end deflection, vapor pockets, and high water table effects; For other than nonenterable underground tanks and for ancillary equipment, the assessment includes either a leak test which satisfies the requirements of §B(3)(e)(i) of this regulation, or other integrity examination, that is certified by an independent, qualified, registered professional engineer in accordance with COMAR 26.13.07.03D, that addresses cracks, leaks, corrosion, and erosion; Develop the written assessment required by §B(1) of this regulation, and have it certified in accordance with §B(2) of this regulation, as follows: For existing underground tanks that cannot be entered for inspection, by January 12, 1988, except that, for tanks that store or treat materials that become regulated as hazardous wastes after July 14, 1986, the owner or operator shall conduct this assessment within 12 months after the date that the waste becomes regulated as hazardous; For all other existing tank systems other than tanks that cannot be entered for inspection, by July 1, 1994, except that, for tank systems that store or treat materials that become regulated as hazardous wastes after July 1, 1993, the owner or operator shall conduct this assessment within 12 months after the date that the waste becomes regulated as a hazardous waste; Comply with the requirements of Regulation .10-6 of this chapter if, as a result of the assessment required by §B(1) of this regulation, a tank system is found to be leaking or unfit for use.