EMPLOYEE WAS IN HIS WELDING SHOP USING A GRINDERON THE DSM SCREEN HOUSING; SPARKS FROM GRINDING LANDED ON HIS JEANS & MATERIAL CAUGHT FIRE. HE IMMEDIATELY EXTINGUISHED FLAME & NOTICED A BURN THE SIZE OF A QUARTER TO 50 CENT PIECE; NO TREATMENT WAS GIVEN AT THE TIME OF INCIDENT. ANINFECTION DEVELOPED AND MEDICAL ATTENTION WAS OBTAINED ON 6/1/2000.