toxicity (n.)

• balefulness
• deadliness
• destructiveness
• harmfulness
• injuriousness
• lethality
• malignance
• malignancy
• malignity
• mischievousness
• noisomeness
• noxiousness
• ominousness
• perniciousness
• poison
• unhealthiness
• venom
• viciousness
• virulence
• virulency