(a) The Department shall develop and adopt regulations for the identification of extremely hazardous substances. An EHSL shall be developed based on at least 1 of the following criteria:

(1) Extremely toxic substances. — Substances are regulated because of their extreme toxicity, ability to disperse and quantity. Each substance shall be assigned a Substance Hazard Index (SHI) number to rank the risk associated with the substance. Substances with an SHI greater than or equal to 8,000 shall be regulated.

The SHI is derived as follows:

SHI=EVCATC

Where:

ATC is the acute toxicity concentration in parts per million defined as the lowest reported concentration, based on recognized scientific protocols, that will cause death or permanent disability to humans from an exposure duration of 1 hour. Extrapolations from various sources of data are permitted using scientifically recognized methods. If toxicity data based on recognized scientific protocols are unavailable, the EHS ATC is set at 10.0 parts per million.

Where:

EVC is the equilibrium vapor concentration at 20°C. defined as the substance vapor pressure at 20°C. in millimeters of mercury multiplied by 1,000,000 divided by 760. For powders, solids or aerosols, the substance vapor pressure is replaced by the maximum substance concentration that can be conveyed in air after a settling distance of 100 meters from the point of emission.

(2) Explosive substances. — Substances are regulated because of their extreme reactivity, instability or explosiveness and creation of associated pressure waves, either inside of confined spaces or in the open atmosphere.

(3) Flammable and combustible substances. — Substances are regulated because of their ability to ignite and burn rapidly, thus creating the possibility of high thermal exposure. Industry standards such as National Fire Protection Association, NFPA 30 may be used as a basis for defining compliance with the terms and conditions of this chapter.

(4) In developing the EHSL to undertake and maintain the delegation of EPA’s authority, the Department shall, by regulation, consider each of the following criterion:

a. The severity of any acute adverse health effects associated with accidental releases of the substance;

b. The likelihood of accidental releases of the substance; and

c. The potential magnitude of human exposure to the accidental releases of the substance.

(b) The Department shall develop and adopt regulations which determine the TQ of each EHS. In developing the TQ for each regulated substance, the Department shall consider the following:

(1) For extremely toxic substances. — The Department shall identify the TQ of EHS that require registration and regulation. For a given EHS, the threshold quantity shall be calculated based on commonly recognized atmospheric modeling procedures and mortality/exposure probabilities calculated for an average individual.

(2) For extremely explosive substances. — The threshold quantity shall be calculated based on commonly recognized procedures to predict the potential impact of a given substance.

(3) For extremely flammable substances. — The threshold quantity shall be calculated based on commonly recognized procedures to predict the burning characteristics, fire size, thermal radiation generation and dissipation with distance and the consequences of a fire. Industry standards such as National Fire Protection Association “Flammable and Combustible Liquids Code” NFPA 30 may be used as a basis for defining compliance with the terms and conditions of this chapter.

(4) In developing the threshold quantities for the EHSL to undertake and maintain the delegation of EPA’s authority, the Department shall, by regulation, take into account the toxicity, reactivity, volatility, ability to disperse, combustibility or flammability of the substance and the amount of the substance which, as a result of an accidental release, is known to cause or may reasonably be anticipated to cause death, injury or serious adverse effects to human health for which the substance was listed.

(c) The Department shall have the power to amend, by regulation, the identification of EHS and the EHSL on the basis of information or scientific data that may become available to the Department.

(d) When the actual quantity of an EHS is greater than or equal to the TQ established by the Department, a responsible person or persons must:

(1) Submit the information required pursuant to § 7708 of this title.

(2) Implement a risk management program pursuant to § 7709 of this title.

(3) Pay the annual fee pursuant to § 7713 of this title.

When the actual quantity of an EHS is less than the TQ or when any other hazardous substance is present at a facility, then responsible person(s) must comply with the general duty statement pursuant to § 7704(a) of this title.

66 Del. Laws, c. 417, § 1; 71 Del. Laws, c. 308, § 1.