Suh M, Yzenas JJ, Proctor DM. 2014. Evaluation of electric arc furnace-processed steel slag for dermal corrosion, irritation, and sensitization. Presented at the Society of Toxicology’s 53rd Annual Meeting, March 23-27, Phoenix, AZ.
Electric arc furnace (EAF) steel slag is alkaline (pH of ~11-12) and contains metals that are known dermal sensitizers, most notably chromium and nickel. As such, EAF slag has potential to cause dermal irritation and sensitization at sufficient dose, but no published study has characterized the potential for dermal effects associated with EAF slag. To assess dermal irritation, corrosion, and sensitizing potential of EAF slag, in vitro and in vivo dermal toxicity assays were conducted following Organisation for Economic Co-operation and Development (OECD) guidelines. In vitro dermal corrosion and irritation testing (OECD 431 and 439) of EAF slag was conducted using human epiderm model. In vivo dermal toxicity and delayed contact sensitization testing (OECD 404 and 406) were conducted in rabbits and guinea pigs. Chemical properties of EAF slag were also characterized. Calcium, iron, silicon and magnesium oxides were the major constituents of EAF slag, each contributing more than 10% of the slag composition. Other elements measured in the EAF slag at higher concentrations were manganese, aluminum and chromium, but nickel was measured at relatively low concentrations. Barium and chromium were the only constituents detected in the TCLP extraction leachate, and they were measured concentrations of 0.798 and 0.250 mg/l, respectively. EAF slag was not corrosive and not irritating in any in vitro and in vivo dermal toxicity tests. The results of the delayed contact dermal sensitization test indicate that EAF slag is not a dermal sensitizer. These findings are supported by the observation that metals in EAF slag occur as oxides of low solubility with leachates that are well below TCLP limits. Metals in slag are tightly fused to the physical matrix limiting the mobility of metal constituents that may be of concern for dermal effects. Based on these results and in accordance to the OECD guidelines, EAF slag is not considered a dermal sensitizer, corrosive or irritant.