Houston ? As many as 1,000 ExxonMobil employees and 14 residents of a senior citizens home were injected with fake flu vaccine, authorities said Friday, and the owner of a home health care company was arrested.

Preliminary tests indicated the syringes were filled with purified water, U.S. Atty. Chuck Rosenberg said. And no ill effects from the shots were reported.

But Hermina Palacio, head of the Harris County health department, recommended that people who received the shots get tested for blood-borne pathogens such as the AIDS virus and hepatitis B and C.

ExxonMobil offered blood tests and counseling to the employees who received the shots at a health fair Oct. 19-20 at the oil company’s complex of refineries and chemical plants in Baytown, just east of Houston.

Iyad Abu El Hawa, 35, was arrested Thursday.