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Addiction and Substance Abuse

Enviromental exposure to cocaine



I received a phone call from my cousin. He told me that he was being evicted from his apartment and needed help on the weekend moving in to a trailer he had purchased. Neither he nor his fiancé’ have a drivers license so I told him I would be glad to help. He asked if I would help him clean out the trailer before he moved in. I went to the trailer and was appalled at its filthy condition. I got to work and started with the kitchen and living room washing the grime and smoke stains off of cabinets, walls, and ceilings using soap and water. I got down on my knees with a brush and scrubbed the kitchen floor. I spent four hours cleaning and agreed to come back the next day and continue to help. The next day, I returned at approximately 3pm and proceeded to help remove some old furniture that needed to be hauled away. When I removed the couch cushions I was surprised to find a pipe which I assumed was for drug use. After examining it for a few moments I tossed it in the trash and continued with the couch. When we tossed it in the drive I noticed that numerous objects including another pipe and a quite a few yellowish white rocks of what after examination I then realized must be crack cocaine. I picked them all up from the drive and pitched them into the trash along with the other pipe. I then went back into the house and proceeded to remove the carpeting from the living room and by the time we were done I had found a substantial amount of what I assumed to be more crack cocaine. When I asked my cousin who lived in this trailer before him he stated that it was occupied by for a long period by several heavy drug users who had been evicted. We then continued to scrub the living room walls, ceiling and floors. After we had completed the living room loaded up as much of the trash as I could into my car, returned home and burned all of it in my burn barrel. I had spent over 10 hours in total in a heavily contaminated trailer cleaning crack smoke off of walls, ceilings and floors. I had handled a substantial amount of crack cocaine and paraphernalia. I was not wearing gloves at any point and had my hands in buckets of water. I had been using solvents to clean the stickier and tougher areas which are readily absorbed by skin. I had burned a large amount of filthy paper towels and rags as well as the crack cocaine I had thrown out. Although I did attempt to stand clear of the smoke I was controlling the burn and added several bags of trash to the burn barrel. The day after, I was informed that I had been selected for a drug test. At the time I gave it not a second thought but in hindsight perhaps I should have been concerned. When I was informed that I had tested positive for cocaine I knew then that perhaps I should have been. I do not take drugs so the situation described above is the only explanation that I can provide for how this positive test has occurred.


Cocaine is available in two major forms, powdered cocaine and a hard form called cocaine base (crack). We know that the powdered form is soluble in water (dissolves easily in water) and is very easily absorbed through mucous membranes (mouth, nose, lips, eyes, etc.) and is a very good local anesthetic. Cocaine base is very insoluble in water and as a result is usually smoked.

Cocaine is one of multiple alkaloids obtained from the leaves of the coca plant. Two species of coca are predominantly used: Erythroxylum coca (found in South and Central America, the Indian subcontinent and Java) and Erythroxylum novogranatense (South America).The leaves are harvested, then treated with a number of solvents. This forms "coca paste", which contains 40 to 90% cocaine. The paste is then treated with baking soda and dissolved in acid to produce cocaine hydrochloride containing about 40% cocaine. Extraction of cocaine hydrochloride with ether in water based or alkaline solution produces "crack", which contains 85 to 90% of pure cocaine.

Cocaine is easily absorbed by snorting (60-80% of cocaine is absorbed), smoking (20 to 60% absorbed) and IV routes (greater than 80 % absorbed). Therefore, how much is absorbed depends on the route used and the form of cocaine. As mentioned earlier, powdered cocaine (cocaine hydrochloride) is easily absorbed through the mucous membranes. "Crack" or cocaine base is more stable, and its major route of absorption is by smoking. Treatment of the cocaine form with different pH solvents can alter the body's absorption.

In acid solutions, cocaine becomes charged (ionized) and does not easily enter into cells. In basic solutions (like many cleaning compounds), there is less ionization, and absorption can be increased. The basic question (no pun intended) here is would this alter the cocaine enough to allow absorption through the skin, assuming that the solution you used to clean with did not destroy the compound. Not knowing exactly what your cleaning agent is makes it difficult to answer the second part of the question. My gut feeling is that degreasers would probably destroy the cocaine or at least minimize any exposure.

Having said this, there are a number of case reports supporting the possibility that environmental exposure can lead to positive cocaine urine toxicology screens. One of the best involves laboratory personnel working in crime labs (Le et al., J Forensic Sci. 1992 Jul; 37(4):959-68). However, the exposure was to powdered cocaine and felt to be secondary to exposure through the lungs and involved individuals handling kilo quantities of cocaine. Another study that supports your case better involves the absorption of powdered cocaine through the skin when applied to the underside of the arm (Baselt et al., J Anal Toxicol. 1990 Nov-Dec; 14(6):383-4). They concluded that skin absorption of cocaine represented a minor, but significant, route of exposure and that it needed to be considered when interpreting low-level urine drug testing results. The major concept here is that the urine levels of cocaine metabolite were low.

No studies analyzed the possibility of skin absorption if handling cocaine base. Could a bunch of cocaine base ("crack") be absorbed through the skin if dissolved in a bunch of cleaning solution? It is improbable that significant absorption would occur, but I could not say that it would be impossible. Having said that, I believe that the results of your urine test could be positive, but that if the test was done to look at the quantity of cocaine metabolite in the urine--it should be very small.

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Response by:

Christina M Delos Reyes, MD Christina M Delos Reyes, MD
Assistant Professor of Psychiatry
School of Medicine
Case Western Reserve University

Nyk   Pidhorodeckyj, MD, MSC Nyk Pidhorodeckyj, MD, MSC
Formerly, Addiction Psychiatry Fellow
School of Medicine
Case Western Reserve University