zachhall.bmpZach Hall, president and top scientist at California’s $3 billion stem cell institute said he will resign from the agency within the next six months.

He cited personal reasons, but he often butted heads with Robert Klein, chairman of the board. The institute is also battling a number of lawsuits which have hampered it from getting its job done. Also leaving is staff member Kate Shreve. Staff member Walter Barnes retired earlier this year, and its PR person Nicole Pagano also left.