Yarn needed: 700yds main color, 200yds contrast color.
The biohazard symbol is given as a colorwork chart. The accompany instructions are for a baby blanket using the yarn and gauge shown, using tunisian crochet stitches, however... don't feel limited to that!
You can knit this baby blanket, or use regular single crochet stitches instead of tunisian crochet.
You can use other yarns and gauges to make an adult size lap blanket
You can put the biohazard symbol on anything else you can think of- a sweater, a felted bag, soakers, a hat, even cross stitch a sign for your bathroom door.