It is normal to experience some smoke when seasoning a cast iron pan in the oven. Seasoning involves heating oil on the pan's surface to create a polymerized layer that provides a natural non-stick coating. During this process, the oil may reach its smoke point, which is the temperature at which the oil starts to smoke.
When the oil reaches its smoke point, it can produce smoke, which is a byproduct of the oil breaking down. This is normal and should not cause any harm unless excessive smoke is being generated. It's important to ensure proper ventilation in your kitchen by opening windows or turning on an exhaust fan to help dissipate the smoke.
If you are experiencing a significant amount of smoke that seems excessive, it could be due to using too much oil during the seasoning process or using an oil with a low smoke point. Make sure to apply a thin layer of oil and use oils with higher smoke points such as vegetable oil, canola oil, or grapeseed oil.
It's also worth noting that the smoke and smell during the seasoning process can be strong, so it's best to do it when you have good ventilation and can tolerate the odor. Over time, as the seasoning becomes more established, the smoke and odor during the seasoning process should decrease.
Remember to follow the manufacturer's instructions or recommended seasoning process for your specific cast iron pan, as different pans may have slightly different requirements.