my hubby is a welder and was told by another welder that the law states that welders are suppose to get a 10 minute break every 45 mins. is this true? also the place where he works refuses to fix the ventilation system, they said the guys are welders and should be use to breathing in the smoke and fumes etc. is there anything they can do to make them fix this?

No, there is no law specific to welders and breaks.

Following is the link to the OSHA regulations on welding and ventilation. If the company is in violation it can be reported to OSHA. http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10699

the place where he works refuses to fix the ventilation system, they said the guys are welders and should be use to breathing in the smoke and fumes etc.

The breaks, as described, are not required by any law. The problem with the fumes could be.

If they believe there are legitimate safety concerns they can contact OSHA.

This is not the type of issue you can just "look at and see". There will need to be air sampling, lab work and time weighted averages all to be factored in before anyone can make a determination wether or not the ventilation meets the criteria for number of complete air changes required in subpart D of the welding,cutting and brazing standard.

I would suggest they invest in filtered and ventilated shields in the mean time.