Buyers working for companies that use chemicals say business could not have been worse in December-January. Worst reports are coming from metals processors while best reports are coming from companies that make such building products as roofing materials and plastic pipe. But, gloomy demand reports notwithstanding, data from PURCHASING'S Chemical Business Survey suggests that a bottom for the CPI segment may not be so far off (see charts). While these little signals certainly don't spell recovery, they do suggest that the deep decline in the CPI is starting to lose steam. There's anecdotal evidence as well. Example: The PM for a firm that uses chemicals for etching and plating flexible circuits says, "We are starting to see some recovery in certain sectors." The PM for a resins maker says, "The industry is awful, but our business is improving selectively."