The discharge of firearms in an indoor firing range produces peak noise levels that exceed the occupational health limits of 140 dB SPL. NIOSH recommends that workers and shooters who use a firing range as part of their occupation (i.e, law enforcement officers) wear double hearing protection (earplugs and earmuffs) as part of an overall hearing conservation program. Special attention must be paid to the use of safety glasses under earmuffs so not to create an acoustical leak and degrade the performance of the hearing protectors.
Exposure to high levels of noise can lead to the following:
• Hearing loss
• Tinnitus (ringing in the ear, which might be permanent)
• Stress
• Anxiety
• High blood pressure
• Gastro-intestinal problems
• Chronic fatigue

NIOSH would like to hear from you regarding your experiences working or training at indoor firing ranges. What prevention methods do you or your employer take? What has worked? What has not worked? Would you be interested in receiving more information or review other products from NIOSH on indoor firing ranges? More information is available in the NIOSH Alert and on the NIOSH Indoor Firing Ranges topic page.
—Chucri A. Kardous, M.S., P.E.

Here is the entire article that address lead exposure as well:
http://www.cdc.gov/niosh/blog/nsb051809_firingrange.html