The post is part of the three-year trust-building project announced six months ago (PRWeek, 28 September 2001).
Lancaster joins from York University where he created and managed the Royal Society of Chemistry's pioneering 'Green Chemistry Network'.
He has been tasked to restore the CIA's reputation by constructing communication lines between chemical companies and communities.
'I see my role as a facilitator, helping companies rectify how they are seen. The industry brings widely-enjoyed benefits, but this is not widely recognised,' said Lancaster, who spent 14 years working for BP before his spell at York.
He reports to CIA communications head John Boler, and incoming director-general Judith Hackitt.
A swathe of redundancies and criticism for lack of environmental awareness has seen the image of the industry tarnished in recent years.
'There has been improvement in the industry that we have to build on using reputation management. But this is not just about spin doctoring.
It's about changing the appearance of the external communications strategy,' said Hackitt.
A year ago the CIA appointed Key Communications following negative press - the first time the organisation had used external PR advisers (6 April 2001).
The UK chemical industry accounts for more than two per cent of GDP and employs 250,000 people.