Possible Clues:

• Fibrous heat-resistant mineral, a cause of mesothelioma
• Sob as ET's drunk toxic stuff
• A cry for help having ingested major toxic material
• A top sketch that's second to none from Duck Soup with lead producing material that's considered very dangerous
• Building material in East London obtains top rating
• Material for which ordinary seaman wins award?
• Boss eats horribly toxic substance
• Old civil orders to detain criminal set producing toxin
• Like first-class seaman that can't be fired?
• Risky material, 'First Love' penned by idiot