What was found
AT FL250, TURNED ON THE WING ANTI-ICE DUE TO RIME ICE BUILD UP, IMMEDIATELY SMELLED A STRONG CHEMICAL ODOR . THE FLIGHT ATTENDANTS DETECTED THE ODOR. LASTED CONTINUOUSLY FOR THE 10 MINUTES OR SO THE WING ANTI-ICE WAS ACTIVE. ONCE TURNED OFF, THE ODOR QUICKLY WENT AWAY. TROUBLESHOT IAW WORKCARD 21202367 FOR PNEU DUCT SMOKE/ODOR, INSPECTED THE CROSSOVER DUCT FOR OIL CONTAMINATION WITH BORESCOPE. NO EVIDENCE FOUND, CONTINUING TO FOLLOW THE WORKCARD. ACCOMPLISHED DUCT BURN OUT PROCEDURES IAW WC 7100-2619 AND WC 2120-2367. NO ODOR PRESENT AT THIS TIME. OK FOR SERVICE.