Sec. 26.10.04.01. Spill and Overfill Control

A. Owners and operators shall ensure that releases due to spilling or overfilling do not occur. The owner and operator shall ensure that the volume available in the tank is greater than the volume of product to be transferred to the tank before the transfer is made and that the transfer operation is monitored constantly to prevent overfilling and spilling.

B. Overfill catchment basins shall be kept clean and dry.

C. Following each removal of a tank fill cap, the cap shall be secured on the fill pipe to prevent liquid or other matter from entering the UST.

D. An underground storage system shall be designed to permit taking direct measurements of content level by the stick method.

E. The owner or operator shall ensure the liquid level of metered storage systems is measured using a stick or electronic method each day of operation, and shall reconcile the results with pump meter readings and receipt of product. These records shall be kept for 5 years at the facility or a location under the control of and designated by the owner or operator and shall be made available to the Department for inspection. Inventories shall be performed in accordance with "Doing Inventory Control Right", USEPA publication 510-B93-044 1993, incorporated by reference in COMAR 26.10.02.06I.

F. Inventory Variations.

(1) Inventory variations exceeding 1 percent plus 130 gallons of the metered quantity of a regulated substance over a period of 30 consecutive days shall be:

(a) Reported to the owner of the UST system; and

(b) Investigated immediately to determine the cause of the inventory variation.

(2) Daily inventory which shows 7 consecutive days of shortage totalling 80 gallons or more, regardless of percent, shall be:

(a) Reported to the owner of the UST system; and

(b) Investigated immediately to determine the cause of the loss.

(3) If, after investigation, the owner or operator determines that there is no indication of a leak, the owner or operator shall state the cause of the variation in the daily inventory records.

G. If the investigation required by §F of this regulation reveals a leak in the UST system, the owner and operator shall follow the procedures of COMAR 26.10.08.

H. The Department may require a precision test if the owner or operator of an UST system has failed to reconcile daily inventory records as specified in §§E and F of this regulation.

I. The Department may require a precision test of the UST system and installation of monitoring wells or a site assessment if there is reason to believe there is or may have been a loss of regulated substance from an UST system.

J. Except for underground storage systems, regulated by COMAR 26.10.03.08 and protected against corrosion and installed as provided in COMAR 26.10.03, and which have release detection that complies with COMAR 26.10.05, an underground storage tank, which has been buried for 15 years or more, or a storage system for which no installation date can be determined, shall meet the following requirements:

(1) It shall be tested for tightness in accordance with a precision test;

(2) The precision test shall be repeated on a storage system at intervals of not greater than 5 years;

(3) Storage systems with a total capacity of 1,000 gallons or less may be tested in accordance with COMAR 26.10.07.

K. The Department may require additional procedures for an underground storage system not having a vent that can be seen by a person positioned at the fill.

L. A high liquid level gauge, an alarm system, or a pump cut-off device shall be installed by the owner or the operator on any underground storage tank from which the Department determines an overflow of oil is possible. Since these emergency devices can fail to operate, their use for spill prevention purposes shall be considered only as auxiliary and supplementary to the use of personnel engaged in the transfer operation.

M. Before each filling of an underground storage system which is not required to maintain daily inventory reconciliation records and which has provisions for measurement of contents, the liquid level shall be gauged and the measurement shall be recorded in writing. These records shall be maintained for 5 years and shall be made available for inspection by the Department.

N. All fill lines for an underground storage system shall be clearly marked to indicate the size of the tank and the type of regulated substance stored. The markings shall be as follows:

(1) A permanent tag or sign installed immediately adjacent to the fill which states the size of the storage system and the specific type of regulated substance being stored; or

(2) A color code shall conform to the following requirements:

(a) Color markings shall be in accordance with API 1637 "Product Identification", which is incorporated by reference in COMAR 26.10.02.06J, and shall be painted or placed around the fill or manhole cover in a manner that will readily identify the regulated substance in the storage system, and

(b) The color code shall be printed on a sign not less than 8 x 10 inches with letters not less than 5/16 inch high, posted at the facility in a prominent location visible from the fill pipe area, and shall be available for inspection at all times to show the tank size and type of regulated substance.

O. Pipes or other openings may not be marked in any way which could be associated with a regulated substance stored at the facility, unless the pipes or openings are used for the transfer of that substance.

P. The owner, operator, and other responsible parties shall report, investigate, and clean up any spills and overfills in accordance with COMAR 26.10.08.04.

Q. A key or other access device shall be kept at the tank location for access to dispensing equipment.

R. Any UST system that stores flammable product or an UST system with a capacity over 1,100 gallons that stores combustible product shall have a drop-tube installed in the fill pipe in compliance with NFPA 30: Flammable and Combustible Liquids.