Also, drywall (plasterboard) came into common use replacing lime plaster on wooden lath. Midland was also the site of a large plant that produced wallboard and plasterboard. These three plants have flue-gas desulphurisation units which supply gypsum for plasterboard manufacture. It is used in combination with wall plugs in masonry, ceramic, wood and plasterboard walls. Traditionally, plaster was laid onto laths, rather than plasterboard as is more commonplace nowadays. BPB was the 100% British producer of plaster and plasterboard. Interior walls were lined with plasterboard. A white plasterboard coffered ceiling incorporates theatrical lighting pods. Boxes for installation within timber/plasterboard walls are usually called "cavity boxes" or "plasterboard boxes". The plasterboard is then applied to the wall using a salt/moisture-proof adhesive. The ceiling has been recently lined with plasterboard. These were subsequently replaced in 2009 with stud-framed plasterboard walls in a new configuration. It comprises a number of offices divided by plasterboard and glass partitions. Some certain components of construction waste such as plasterboard are hazardous once landfilled. The steel columns are lined with plasterboard and painted.