The next public involvement plan meeting for the Raytheon hazardous waste cleanup site on Boston Post Road will take place at 7:30 p.m. Wednesday in Town Hall. Raytheon will provide a summary of the cleanup operation during the meeting. Documents about the site can be found at the Board of Health or at www.ermne.com. The site had been operated as a research and design facility by Raytheon Co., and is now a vacant office park.