Scale effect would decrease wages and employment for everyone. As costs increase, production decreases, and so does the level of demand for employment. For the same quality worker, total compensation must be equalized. For those who aren't receiving health insurance, there was possibly some reason before, such as workers valued increased pay over health benefits. Additionally, we might see employment decrease among these workers alot if we have a binding minimum wage, and wages cant decline enough to compensate for the increased cost of health benefits. On the other hand, substitution effect would shift us towards a preference for part-time workers, as opposed to full time, because the quasi-fixed cost of employing part-time workers if not reduced relative to full time. Firms which don't currently provide insurance to some workers may prefer to reduce hours of those workers and higher additional part time workers as a cheaper alternative to providing health insurance to all full time workers.