COUNTY OF SAN DIEGO BOARD OF SUPERVISORS WEDNESDAY, APRIL 20, 2005 MINUTE ORDER O. 11 SUBJECT: ADMINISTRATIVE ITEM: SECOND CONSIDERATION AND ADOPTION OF ORDINANCE: REPEAL OF AN ORDINANCE REQUIRING METHANE TESTING ON PROJECTS WITH MASS GRADING (DISTRICTS: ALL) OVERVIEW: On April 13, 2005 (4), the Board of Supervisors introduced the Ordinance for further Board consideration on April 20,2005. FISCAL IMPACT: RECOMMENDATION: CHIEF ADMINISTRATIVE OFFICER Adopt an Ordinance entitled. AN ORDINANCE REPEALING CHAPTER 3 OF DIVISION 6 OF TITLE 8 OF THE SAN DIEGO COUNTY CODE RELATED TO METHANE GAS TESTING IN THE UNINCORPORATED AREAS OF SAN DIEGO COUNTY ACTION: ON MOTION of Supervisor Jacob, seconded by Supervisor Cox, the Board of Supervisors took action?as recommended, on Consent, adopting Ordinance No. 9713 (N .S.) entitled: AN ORDINANCE REPEALIN CHAPTER 3 OF DIVISION 6 OF TITLE 8 OF THE SAN DIEGO COUNTY CODE, RELATED TO METHANE GAS TESTING IN THE UNINCORPORATED AREAS OF SAN DIEGO COUNTY. AYES: Cox, Jacob, Slater?Price ABSENT: Roberts, Horn State of California) County of San Diego) I hereby certify that the foregoing IS a full, true and correct copy of the Original entered in the Minutes of the Board of Supervisors. THOMAS J. PASTUSZKA Clerk of the Board of Supervisors By?g?lw? av: all, Deputy 04/20/05 04?20?05 (11) ORDINANCE NO.9713 (N.S.) AN ORDINANCE REPEALING CHAPTER 3 OF DIVISION 6 OF TITLE 8 OF THE SAN DIEGO COUNTY CODE RELATED TO METHANE GAS TESTING IN THE UNINCORPORATED AREAS OF SAN DIEGO COUNTY The Board of Supervisors of the County of San Diego ordains as follows: Section 1. Purpose and Intent. The Board of Supervisors finds and determines that since the methane?testing ordinance at Chapter 3 of Division 6 of Title 8 of the County Code became effective in August 2001, and was amended in March 2002, subsurface methane gas has been tested at projects in several areas of the County including Fallbrook, Vista, Escondido, Santa Fe Valley, San Dieguito and Valle de Oro. In each of these occurrences, the subsurface. methane gas exhibited very similar characteristics, including the following: 1) the gas was not under pressure, 2) the gas was found almost exclusively in engineered fill soils; 3) the gas was found only in small volume; and, 4) the source of the subsurface methane gas is associated with the natural degradation of organic materials. Because the subsurface methane gas is not under pressure and is associated with small amounts of organic materials in engineered fills, the potential risks are much lower than with other types of occurrences, such as landfills or oil walls. This determination was supported with the completion of a computer modeling, which found that despite the numerous layers of conservatism built into the simulations a constant methane gas generation rate, high number of crack slabs and non-gastight moisture barriers, absence of sub-slab venting, high gas concentration, and low interior pressure) the model showed that potentially hazardous concentrations of methane would not accumulate on the interior of a structure, even under worst?case scenarios in the absence of methane mitigation measures. Based upon the science available, methane mitigation measures for structures located on mass graded sites do not appear to be warranted. Section 2. Chapter 3 of Division 6 of Title 8 of the San Diego County Code is hereby repealed. Section 3. This ordinance shall take effect and be in force thirty days after its passage, and before the expiration of fifteen days after its passage, a summary hereof shall be published once with the names of the members of this Board voting for and against it in the W, a newspaper of general circulation published in the County of San Diego. APPROVED AS TO FORM AND COUNTY COUNSEL BY SENIOR DEPUTY SILEIOS PASSED, APPROVED, AND ADOPTED by the Board of Supervisors of the County of San Diego this 20th day of April, 2005. AM SLATER-PRICE Chairwoman, Board of Supervisors County of San Diego, State of California The above Ordinance was adopted by the following vote: AYES: Cox, Jacob, Slater-Price, Roberts, Horn ATTEST my hand and the seal of the Board of Supervisors this 20th day of April, 2005. THOMAS J. PASTUSZKA Clerk of the Board of Supervisors By 0? <3 4 Claire Tosh, Deputy No. 9713 (N.S.) 04-20?2005 (1 1)