Spitzer Space Observatory IRAC and MIPS photometric observations are presented for 20 white dwarfs with Teff . 20, 000 K and metal-contaminated photospheres. A warm circumstellar disk is detected at GD 16 and likely at PG 1457−086, while the remaining targets fail to reveal mid-infrared excess typical of dust disks, including a number of heavily polluted stars. Extending previous studies, over ...
