The LD50 (median lethal dose) for THC (Delta 9 Tetrahydrocannabinol) is not precisely known, as there have been no recorded fatalities. Hash oil can contain up to 80% THC, though up to 99% is possible with other methods of extraction. While health issues of the lungs may be exacerbated by use of hash oil, it is not known to cause side effects not already found in other preparations of cannabis.