Nicotine cartridges/filters can contain anywhere from 6-36 mg of nicotine–about the same amount as in a cigarette. The bottles of liquid used to recharge the cartridges (e-liquid, e-juice) contain up to 36 mg nicotine/mL and come in 10-30 mL bottles (30 mL was largest I was able to find), so can contain as much as 1080 mg of nicotine.
So the bottles of the e-liquid could easily be fatal if the contents were ingested. The LD50 of nicotine in dogs is 9 mg/kg (lower in humans) so even a 10 mL bottle of 6 mg/mL (the lowest nicotine strength) could easily prove fatal if the contents were ingested.
