If, at the sole discretion of the Department, the Department determines that a tank or UST system permanently closed-in-place before December 22, 1988, may pose a current or potential threat to human health and the environment, the Owner or Operator of such a tank or UST system shall upon notice from the Department conduct a site assessment in accordance with 310 CMR 80.43(4).
310 CMR, § 80.46