Provided photo of Shell plant in Geismar.

DONALDSONVILLE — Without discussion Tuesday, the Ascension Parish School Board unanimously approved  a decade-long property tax exemption for a potential major expansion at Shell Chemical's Geismar plant, joining the Sheriff's Office and Ascension Parish Council in signing off on the exemptions.

The School Board, which receives the largest portion of property taxes in Ascension Parish, would forgo $62.5 million in property tax revenues over the 10-year life of the exemption for the $1.2 billion expansion.

If the project lands in Geismar, the school district would receive $15.6 million in new property tax revenue from the Shell expansion over the 10 years, according to information from the parish Assessor's Office.

The project is expected to have a huge economic impact, bringing in more than 1,000 temporary construction jobs, with a projected $7 million to $10 million in sales tax collections in Ascension Parish during the construction phase.

The proposed new unit would bring 23 new permanent jobs to the Geismar site, with an estimated payroll of $2.3 million per year. 

The plant manager for Shell's Geismar site, Rhoman Hardy, has said Shell Chemical is considering 17 potential sites for the $1.2 billion expansion, a plant to produce monoethylene glycol, used to make antifreeze and plastic, that would be five times the size of the current such plant at the Geismar site.

After the meeting, Hardy said Shell is expecting to make its decision by the end of this year on where to build the plant. 

Under current regulations for the state's Industrial Tax Exemption Program, companies need the approval of the major taxing bodies in a parish before the state will exempt manufacturers from paying 80 percent of their property taxes for 10 years.

School Board Vice-President Troy Gautreau made the motion for approval, seconded by board member Louis Lambert.

Follow Ellyn Couvillion on Twitter, @EllynCouvillion.