Excerpt: [E]mployers that don't bring health care plan costs under control eventually would be exposed to a new 40% federal excise tax on health insurance premiums that exceed certain levels. In addition, employers could face assessments of $3,000 a year per employee if employees' share of health care premiums fails a new affordability test. Employers most likely to be affected by the health reform changes will be those whose workforces are comprised largely of lower-wage workers paying premiums that exceed what the legislation defines as affordable, experts say.