ESCONDIDO–A fatal vehicle collision Tuesday afternoon in Escondido claimed the life of an elderly couple, authorities report.

Just after 1 p.m., a 27 year old female, from Escondido, was driving a 2007 Ford Explorer Sport Trac westbound on Lilac Road. At the same time, an 83-year-old male, from Valley Center, was driving his Mercedes E300 eastbound on Lilac Road, according to California Highway Patrol.

According to a witness, for an unknown reason, the Ford Explorer crossed over the double yellow center line and collided head-on into the Mercedes E300.

The driver and passenger, an 81-year-old female from Oceanside, of the Mercedes E300 were pronounced deceased at the scene. The driver of the Ford Explorer was life-flighted to Palomar Hospital with major injuries and was arrested for suspicion of driving under the influence of drugs,

At the time of the collision, the Ford Explorer was carrying pool cleaning chemicals. Due to the collision, the chemicals spilled, which resulted in the closure of Lilac Road. The roadway was re-opened at 6:14 p.m.

The collision remains under investigation.