Can you legally refuse to work without being penalized for it?
If a situation presents an obvious hazard but there's no clear risk of real physical harm or death, you should report the issue to the Occupational Safety and Health Administration (OSHA). Keep in mind that there's a huge difference between the potential of harm and a near certainty of it.
If the danger is immediate, and there's no way to alert OSHA in advance, you need to do the following:
1. Alert your employer, if at all possible.
2. Ask your employer to assign alternate work, if something else can be done while the danger is addressed.
3. Let your employer know that the danger is too extreme -- you won't begin work until the hazard is cleared.
4. Do not leave the job site unless your employer tells you to leave.
It's important in situations like this that any reasonable person looking at the situation would agree the condition is too hazardous in which to work. For example, if a co-worker was previously injured and bled profusely around and on the equipment, you'd be justified in refusing to handle the equipment until the biological hazard caused by the blood was cleared.
An employer cannot terminate you for either refusing to work when your refusal is made in good faith -- or for making a report to OSHA.
If an employer does wrongfully terminate you in retaliation for refusing to work under those kinds of conditions or for making a report, consider exploring your legal options.