Mike has a good point about the ventilation. What you smell with PR resin is the styrene. It's not super toxic like nerve gas, but you shouldn't expose yourself (or anybody else) any more than necessary. How much of a problem it is will, to a certain extent, depend on what volume you are working with. Mixing up 1 oz for a "tube in" pen blank cast will not be nearly as much of an issue as mixing up a couple gallons for a mass production blank pour. The effects of styrene exposure will compound over time. Initially you may have no noticeable effect from the styrene. Some people even like the smell (I'm not one of them). With enough exposure you will become sensitized and quickly develop severe reactions to the styrene. This is best avoided.
Whether I'm working with 1/8 oz or much larger amounts, I wear a respirator and protective goggles. The respirator will filter out the styrene and the goggles keep anything from getting into the eyes. PR in the eyes would be bad. MEKP in the eyes could be disastrous. It only takes one slip to ruin your life. Use safety gear.
I always use nitrile gloves. They are cheap (at HF in bulk) and I can get multiple casting sessions out of a pair of gloves.
Having protected yourself, you need to worry about anybody else in the area. Small molds can be enclosed (cheap glad containers work) to contain the fumes during curing. Or they can be moved outside during warmer weather (70 minimum temps). An exhaust fan will help in a lot of situation to get the fumes out of the shop (and attached buildings).
You can cast outdoors (balcony) if the temps are warm enough and other weather conditions allow. I open the garage door when I'm casting, aim a fan out the door and move my molds outdoors (under cover) after pouring for curing. A couple of minutes after the molds leave the shop, tools are cleaned and waste is disposed of in sealed bags, there is no residual smell.
When the weather doesn't allow me to have the door open my wife complains about the smell when she comes out to the shop. Even a couple of hours after I've finished casting.
I'm with Mike, I would not use PR in a basement.
Keep in mind that tens of thousands of people work with PR resin every day and they aren't dropping dead left and right. But the stuff can kill you or cause severe harm if not used properly. Good work practices, safety gear and common sense can minimize the risks.
Just some thoughts.
Ed