It is unlikely that a person would overdose on nicotine through smoking alone. The US Food and Drug Administration (FDA) stated in 2013: "There are no significant safety concerns associated with using more than one [over the counter] OTC [nicotine replacement therapy] NRT at the same time, or using an OTC NRT at the same time as another nicotine-containing product—including a cigarette."[22][23][24] Ingestion of nicotine pharmaceuticals, tobacco products, or nicotine containing plants may also lead to poisoning.[4][5][6] Smoking excessive amounts of tobacco has also led to poisoning; a case was reported where two brothers smoked 17 and 18 pipes of tobacco in succession and were both fatally poisoned.[7] Spilling an extremely high concentration of nicotine onto the skin can result in intoxication or even death since nicotine readily passes into the bloodstream following skin contact.[25][26]