IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-ISSN: 2279-0861.Volume 13, Issue 9 Ver. II (Sep. 2014), PP 83-93 www.iosrjournals.org www.iosrjournals.org 83 | Page The Effect of Formaldehyde Vapour on the Lungs of Rabbits Ochei Kingsley Chinedum 1 , Omeh Yusuf Ndukaku 2 , Obeagu Emmanuel Ifeanyi 3 and Obarezi Thompson Ndubuisi 4 1. Department of Medical Laboratory Sciences, Faculty of Basic Medicine, Ambrose Ali University Ekpoma, Edo State, Nigeria. 2 .Department of Biochemistry, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. 3. Diagnostic Laboratory Unit, University Health Services Department, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. 4.Medical Doctor, University Health Services Department, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. Abstract: Formaldehyde is an organic compound with the formula CH 2 O and it is the simplest aldehyde, with systematic name methanol. The aim of this investigation was to sensitize embalming laboratory users of the impending danger associated with overexposure to forty percent (40%) formaldehyde vapour (the active component of embalming fluid) on the lungs. Twenty adult male albino rats were used for this investigation. The animals were divided into five (A, B, C, D, and E) groups. Animals in group B, C, D and E were respectively exposed to forty percent( 40%) formaldehyde for ten(10), fifteen(15), twenty(20) and twenty five(25) days while animals in group A which serve as control group were not exposed to forty percent (40%) formaldehyde at all. At different stages of the experiment, the animals in each of the group were decapacitated and the thoracic cage cut open to expose the lungs. The lung tissue was processed for light microscopic investigation adopting the Haematoxylin and Eosin (H and E) staining procedure. The histopathological observation in this study showed that exposure to forty percent (40%) formaldehyde induced changes in the histology of the lungs. The observed changes were duration dependent. So forty percent (40%) formaldehyde may be able to have greater marked effect at a prolonged exposure. These findings suggests that forty percent (40%) formaldehyde vapour may be remarkably toxic on the rat lung tissue and advocate for precautionary measure for human handlers while handling this chemical especially in the histopathology unit for fixation and embalming purposes. Keywords: Embalming, Histopathological, Haematoxylin and Eosin. I. Introduction Embalming is the process of disinfecting, preserving and restoring a deceased human body to a more lifelike appearance and this process modifies tissue constituents in such a way that the tissue architecture will be retained (Metcalf et al., 1991). However, there are different ways of carrying out embalmment but the most common is the adoption of chemical Solutions and this was first practiced by the Americans by the use of chemical arterial embalming as early as 1980’s (Günther, et al., 2002). The most commonly used chemical solution is formalin and the active chemical of choice in most of the embalming laboratories is formaldehyde with the embalming fluid being prepared by mixing some percentage of formaldehyde with different other chemicals (Weast, 1981). Moreover, the mixture formula of this fluid varies depending on the laboratory and some other factors such as the size of organ, oedema and stage of decomposition (Weast, 1981). Though, formaldehyde is also been utilized by chemical industries such as those involved in manufacturing of resins, paper, pharmaceuticals, leather goods, and other products (ANICNA 2007). Interestingly, formaldehyde is water soluble and as such readily absorbed through the lungs and gastrointestinal tracts and to a much lower extent through the skin (Cary and Sullivan 1992). Formaldehyde is an organic compound with the formula CH2O and it is the simplest aldehyde, with systematic name methanol. Formaldehyde is a colourless gas with a characteristic pungent odour with important precursor to many other chemical compounds, especially for polymers. In 2005, annual world production of formaldehyde was estimated to be 23 million tonnes (50 billion pounds) (Günther, et al. 2002). Commercial solutions of formaldehyde in water, commonly called formalin, were formerly used as disinfectants and for preservation of biological specimens. Formaldehyde is more complicated than many simple carbon compounds because it adopts different forms. Formaldehyde is a gas at room temperature, but the gas readily converts to a variety of derivatives, which are often used in industry in place of the gas. When dissolved in water, formaldehyde combines with water to form methanediol or methylene glycol H 2 C(OH) 2 . The diol also exists in equilibrium with a series of oligomers (short polymers), depending on the concentration and temperature.