§ 505. Uses Involving Toxic or Hazardous Materials

A. Purpose. These regulations are intended to protect the groundwater underlying the Island since it is the sole source of the Town's existing and future drinking water and is integrally connected with and flows into the surface waters, ponds, streams and coastal estuaries which constitute significant recreational and economic resources of the Town, and since accidental spills and discharges of petroleum products, other toxic and hazardous materials, and sewage threaten the quality of such groundwater and related water resources. The sole source aquifer condition of the Island calls for stringent means to insure the purity of the water system and its watershed.

B. Use Regulations.

1. Any use otherwise permitted as of right which involves the manufacture, storage, use, transportation or disposal of toxic or hazardous materials as well as any use permissible by Special Use Permit which involves toxic or hazardous materials, shall conform to the applicable provisions of Article 4, Standards for Uses Allowed by Special Use Permit, and to the requirements of this Section. Such uses include but are not limited to: municipal sewage treatment facilities with on-site disposal of primary or secondary treated effluent, road salt stockpiles, and any other use which involves the manufacture, storage, use, transportation or disposal of toxic or hazardous materials including but not limited to automotive service and repair, dry cleaning, electronic circuit assembly, metal plating, painting, wood preserving and furniture stripping, pesticide and herbicide application, photographic processing, printing.

2. Applicability. This Section shall not apply to uses involving toxic or hazardous materials in quantities associated with normal household use, maintenance or repair, and shall be exempt from this Section.

C. Requirements.

1. Water Quality. Groundwater quality resulting from on-site waste disposal and other on-site operations shall not fall below state or federal standards for drinking water at the down gradient property boundary (5 ppm concentration of nitrate-nitrogen and other relevant chemicals under the Federal Safe Drinking Water Standards).

2. Safeguards. Provision shall be made to protect against toxic or hazardous materials discharge or loss resulting from corrosion, accidental damage, spillage or vandalism through measures such as: prohibition of underground fuel storage tanks; spill control pro-visions in the vicinity of chemical or fuel delivery points; secured storage areas for toxic or hazardous materials; and indoor storage provisions for corrodible or dissolvable materials. For operations which allow the evaporations of toxic or hazardous materials into interiors of any structures, a closed vapor recovery system shall be provided for each such structure to prevent discharge of contaminated condensate into the groundwater.

3. Disposal. For any toxic or hazardous wastes to be produced in quantities greater than those associated with normal household use, the applicant must demonstrate the availability and feasibility of disposal methods which are in conformance with accepted state/federal standards.

4. Drainage. All run-off from impervious surfaces shall be recharged on the site, diverted towards areas covered with vegetation for surface infiltration to the extent possible. Dry wells shall be used only where other methods are not feasible and shall be preceded by oil, grease, and sediment traps to facilitate removal of all contaminants.

5. Risk Analysis. No use shall be approved which creates a risk to groundwater quality. Risk shall be determined by weighing the simplicity, reliability and feasibility of the control measures proposed against the degree of threat to water quality which would result if the control measures failed.

D. Special Procedures.

1. Review. All proposals governed by this Section shall be subject to Development Plan Review by the Planning Board. The Planning Board shall transmit application material to the Conservation Commission for its review and comment, and such comment shall be considered by the Planning Board if submitted to it in writing within forty-five (45) days of receipt by the Conservation Commission.

2. Submittals. In applying for a Special Use Permit required by this Section, the information listed below shall be submitted:

a. A complete list of all chemicals, pesticides, fuels and other potentially toxic or hazardous materials to be used or stored on the premises in quantities greater than those associated with normal household use, accompanied by a description of measures proposed to protect all storage containers/facilities from vandalism, corrosion and leakage, and to provide for control of spills.

b. A description of potentially toxic or hazardous wastes to be generated, indicating storage and disposal methods.

c. Projections of down-gradient concentrations of nitrogen and other relevant chemicals (e.g., Federal Safe Drinking Water Standards chemicals) at property boundaries and other locations deemed pertinent by the Zoning Board of Review. Projections shall be based upon appropriate groundwater models and guidelines available at the Town Hall and from the Conservation Commission.