How do I confront my roommate regarding their childs safety

I have a roommate who has their child with them half of the week. Their child is very young (toddler - early childhood age) and I agreed to letting them stay with me under the impression that they are clean and quiet people (I know children are never really quiet but as someone who has raised quite a few, I don't mind noise). There are issues with our living situation now regarding cleanliness, bringing bugs into the house and general treatment of my space. The safety of the child has become a huge issue for me.

My roommate and I don't really communicate much asides from the usual "Hi" and "Do you want to shower first?" so this is going to be a difficult conversation for us to have. However, it needs to happen. Here is a list of the offenses:

The other day I came home from work and walked in the kitchen and noticed that there were pills on the floor. Not the big supplement pills but tiny white pills. I grew concerned when I noticed more than one pill on the floor.

I cleaned the bathroom and saw packaged needles on the floor. Individual needles in a small container (how they have at the doctors office) just laying on the floor of the bathroom. I immediately picked them up and interrupted their phone call and asked what the needles were and why they were on the floor. They said that the needles were for piercings, ok.

I got home from work and saw that my kitchen scissors were laying open on my couch. My animal immediately jumped on the couch and landed on the scissors.

I have a small blow torch that I use for cooking that I keep on a high shelf so the child cant reach it. The other day I found the blow torch on the floor.

There is lost weed in the apartment. They cannot find their weed and suspect that maybe the child got into it.

These are just a few of the things that have alarmed me as the child is not supervised often. The roommate will often be in one room and leave the child to entertain themselves or will yell at the child to leave them alone if they are doing something. We are having a discussion soon regarding the condition they are leaving my house in and how since they have moved in, I now have roaches. With this discussion being scheduled, I need to address my concerns but I don't know how to bring it up as this is not MY child. However, the welfare of the child while they are living in my house is my concern because god forbid something happen to the child, it will have been under my roof with me being a witness to all of this. Please, any tips or advice is welcome.

I do want to edit this to say I looked up the needles and they are indeed piercing needles. Also just based off of this person and how they act and their day to day routines I don't think they are shooting anything. I may be wrong but they have given me no indication that they use needles to do drugs. I still don't know what the pills are but I will find out later. Edit: pills are an anti anxiety medication