Industrial Hygiene Success Story
Case 2: Contractor Lead Exposure During Firing Range Clean-Up
Scott Brueck, CIH, Art Wickman, CIH, and Michelle Dunham
On December 18, 2000, an industrial hygiene air monitoring survey was conducted for a small contractor engaged in clean-up of an indoor firing range in which lead bullets were used as ammunition. The firing range, with a floor measuring approximately 200 x 100 x 20 feet was used daily by US Government personnel for firearms training. The facility was typically cleaned on a weekly basis. Cleaning consisted of the following activities:
- cleaning of a stainless steel counter area where firearms are disassembled, cleaned, and reassembled after training sessions with a liquid all-purpose cleaner;
- dry sweeping dust and debris away from the side walls of the facility;
- sweeping the main floor of the facility with a Tennent industrial floor sweeper (not equipped with a HEPA filter) and emptying the sweeper into a 55-gallon waste drum; and
- dry sweeping the target area of the facility and dumping dust and debris from dust pans into 55-gallon waste drum.
During cleaning activities employees wore half mask respirators equipped with HEPA filters, safety glasses, tyvek coveralls, and gloves. Three employees were actively involved in clean-up activities which took a total time of approximately 2 hours. Following clean-up employees removed their PPE and washed their hands. Although employees were exposed to lead for only the two hours they were engaged in clean-up of the firing range, results of air monitoring revealed that all three monitored employees' 8 hour time-weighted average exposures to lead exceeded OSHA's action level of 0.03 mg/m3 and one of the employee's exposure was nearly double the OSHA PEL of 0.05 mg/m3. Exposures were particularly elevated during dry sweeping activities. Notably, one of the employees time-weighted average lead exposure during dry sweeping of the target area was 16 times greater than the PEL concentration.
Other problems related to lead exposure noted during the survey were no effective control measures to prevent excessive lead exposure, lack of an employee training program regarding lead exposures, no previous air monitoring data or a periodic air monitoring schedule, employees had not been provided with medical evaluations and blood lead monitoring, no shower immediately available for use, and signs were not posted to warn employees of the presence of lead. Problems related to respirator use included no respiratory protection program including no medical evaluations, fit testing, and training. Employees were also observed wearing the respirators improperly and two of the employees had beards, which prevented proper fit. Following the survey, the company decided to reduce lead exposures through the use of new equipment and work practice procedures specifically the following controls were implemented:
- Water was used to wet the surface area of the target area prior to sweeping. Water was also use to wet the interior of the waste drums and the interior of the industrial floor sweeper dust container prior to dumping dust and debris;
- A HEPA filtered vacuum was purchased for cleaning of the target area of the range; and
- The size of the work crew for cleaning of the range was increased to 5 employees to reduce the time needed for cleaning activities.
Follow-up air monitoring, conducted in May 2001 revealed that employees 8 hour time-weighted average exposures to lead had been reduced to below the action level of 0.03 mg/m3, indicating that their exposure control measures were successful in reducing exposures. Blood lead monitoring revealed that employees had blood lead concentrations well below OSHA limits.