Multi-stage ranking of emergency technology alternatives for water source pollution accidents using a fuzzy group decision making tool

•The scenario suitability analysis for technologies was performed via multiple stages.•An interval-valued trapezoidal fuzzy group technique evaluation tool was developed.•A combination of Spearman’s rho and Group-G1 was used for weight determination.•The threat estimation system and technique evaluation system were established.•Different technique evaluation index weights correlated to threat levels were set up.