The purpose of the current study is to qualitatively explore how Thai preservice biology teachers make decisions on, and informally reason about, an agriculture-based socioscientific issue (SSI). The SSI arises mainly as a controversy between two social classes, namely the agricultural and non-agricultural sectors, involving haze pollution. Participants comprised 45 fourth-year preservice biology teachers (11 males and 34 females) almost equally divided between the two sectors. They completed a written questionnaire asking for the level of their concern, their reasons for concern, and their positions regarding a solution to haze pollution -- that is, the banning of agricultural burning. Data were inductively analysed using an iterative process of coding and categorising. The results suggest that, while they shared the main concerns about health and the environment, the participants from different sectors tended to approach the issue differently. While this difference must be confirmed with a larger population, it supports the hypothesis that socio-professional identities play a role in the process of decision-making and reasoning regarding SSIs. It is recommended that the socio-professional identities of those engaging in SSIs should be explicitly considered in the context of SSI-based instruction.