Exxon Mobil operates a chemical plant in Baton Rouge, but is also working on a proposed $9.3 billion facility that would go either in Texas or Louisiana, with Ascension and St. James parishes under consideration.

The school board in a south Texas community competing with two Louisiana sites has approved an estimated $1.2 billion in tax breaks to entice Exxon Mobil Corp. and its Saudi partner to build a $9.3 billion petrochemical plant within its district along the Texas Gulf Coast.

Earlier this year, Exxon Mobil officials said Ascension and St. James parishes are in the running for the petrochemical complex, though company officials have said the Portland, Texas, site is the front-runner and another Texas site is also under consideration.

The company said Thursday that Exxon Mobil and Saudi Arabia Basic Industries Corp. have not yet selected a site.

"Given that the tax abatement votes were slightly postponed, we can now begin final reviews with our partner SABIC," Exxon said in a statement. "We expect to be closer to making a final site selection in the next 60 to 90 days. Until then, we will continue to evaluate the four sites under consideration."

Louisiana Economic Development Secretary Don Pierson said his agency "continues to do everything within our power to attract the highest-quality investments and best jobs for our state. For projects that remain in confidential negotiations, we respectfully reserve comment until a later date when proprietary prospect information and incentive details have been finally determined and can be made public upon announcement at the appropriate time."

The six-member Gregory-Portland Independent School District board's unanimous vote late Tuesday adds to a $210 million tax package passed a day earlier by San Patricio County commissioners.

Exxon and Saudi Arabia Basic Industries Corp. are considering a 1,300-acre site in Portland, just north of Corpus Christi, for the world's largest ethane steam cracker plant. It would convert natural gas into chemicals used for plastics.

The plant, scheduled to open in 2024, also would provide thousands of jobs.

The school board vote came despite a petition signed by 1,500 people who oppose the plant, citing safety and environmental concerns. The plant would be less than 2 miles from the district high school.

Previously, Portland's city council approved a resolution asking Exxon Mobil to rule out their city as a site.

Under terms of the school board tax plan, the district would limit the taxable value of the new plant at $90 million for 10 years, cutting the district's tax revenue from an estimated $120.9 million per year to less than $1.2 million per year.

The county's separate tax abatement package would cover seven years.

The project still needs state approval and Exxon and its Saudi partner are considering a Texas site in Victoria, about 70 miles to the north, and the two in Louisiana.

"If we do choose the Gregory-Portland site as our location, I want to assure you that we will follow through with our Good Neighbor Commitments on health and safety, quality of life, education and workforce development, and being good environmental stewards," project leader Robert Tully told residents in an email Wednesday, according to the San Antonio Express-News.

The tax breaks also are contingent on job creation. Project leaders have committed to the Texas Comptroller's Office more than 15,000 temporary construction jobs. The tax abatements require Exxon to employ a minimum of 400 people and seek an alternate water source if local water sources become scarce.