I doubt many would want to work there and risk 14+ years in prison for assisting a suicide. More if they try to prosecute for murder. In many countries, it's illegal to assist a suicide. In those it isn't, the requirements to apply for assisted suicide are very tight.
Kenneth Law is facing 14 counts of counselling and aiding suicide and 14 counts of first degree murder for knowingly selling SN for the use of suicide.
SN is really more innocuous than nembutal too. It does at least have other non lethal uses. I suppose those in the factory could claim they thought they were making it for pet euthanasia. The people involved in distributing it likely would have less to hide behind. Maybe they could market it for animal use but, someone will no doubt blow their cover. Kenneth Law ended up coaching people how to suicide with SN.
Plus, I'm sure it's restricted as a controlled substance in most places. So- to manufacture and sell it I imagine would be illegal.