Background: Chemicals from laboratories represent a significant risk in cellular mediated hypersensitivity (CMH) and chemo-induced skin injury due to chemical agents present under human skin layers absorbed from the surface. This study aimed to determine the occupational and socio-demographic characteristics of the laboratory workers associated with CMH in multiple chemical exposures. Design: This was a cross-sectional study on a population-based sample of Nigerian laboratory university workers. Methods: Data were collected using the erythema index meter. The study included 287 laboratory workers. Results: The results showed that the number of positive with CMH was 176 (61.3%) with 99 (56.3%) of them were male with AOR 0.31 (95%CI: 0.12, 0.77; p=0.011). Dark-skinned participants with CMH had adjusted odd ration, AOR 0.49 (95%CI: 0.21, 081; p =0.001). Most of the respondents have college education and have been exposed for 4-5hrs in the laboratory with AOR 2.42 (95%CI: 1.10, 5.38; p = 0.049) and 3.11 (95%CI: 1.77, 9.23; p =0.001) respectively. The use of personal protective equipment (PPE) was 60% less likely to be significantly induced with CMH with AOR 0.40 (95%CI: 0.22, 0.77; p =0.011). The Permissible exposure limit (PEL) of chemical was less but have an induced CMH with AOR 4.22 (95%CI: 2.88, 12.11; p =0.004). Conclusion: Results revealed that sex, skin color, working experience, educational level, PPE, PEL, and time of exposure were the probable predictive factors associated with the development of CMH. This study has shown that CMH was significantly associated with occupational and demographic factors. Better educational knowledge and attitude of hazards and safety in the laboratory would lead to a reduced rate of new cases.

Background: This study aimed to develop adhesive from waste polystyrene, which has the capacity to both reduce environmental pollution and create wealth from waste. Methods: Polystyrene waste was obtained from waste heap “bola” around Jimeta metropolis, Yola, Adamawa State, Nigeria. The polystyrene waste was washed and dried. The washed waste was used to formulate adhesive using various solvents such as toluene, gasoline, blend of gasoline and toluene, and blend of gasoline and acetone. The formulated adhesives were characterized by study some physical properties of the formulated adhesive, such as; viscosity, bond strength, pH, solid content, moisture content and drying time. Results: The adhesive formulated from the blend of toluene and acetone gave the best performance from the physical properties. The adhesive from blend of toluene and acetone as solvent was then selected for application on different surfaces such as plastic, plywood, aluminum, glass and ceramic. The Bond strength of the selected adhesive was measured on these surfaces as follows; plastic (6.74 MPa), ceramics (5.9 MPa), glass (5.9 MPa), plywood (7.04 MPa) and aluminum sheet (0.76 MPa). The pH of the adhesive was 6.58, viscosity;467, drying time; 2.44minutes, solid content (% SC); 90.62 % and the moisture content (% MC) of the adhesive was 9.38 %. The adhesive on optimization, established that increase in concentration of polyvinyl acetate impact greatly on the bond strength of the adhesive. Glycerol was used as plasticizer that improved the flexibility of the adhesive but it raises the moisture content (% MC) of the adhesive. Conclusion: It was concluded that creation of wealth while reducing environmental pollution, through production of environmentally friendly adhesive from waste plastics, is a viable task. This research hereby introduces a new adhesive to the adhesive industry