Success Stories

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:

1. cleaning of a stainless steel counter area where firearms are disassembled, cleaned, and reassembled after training sessions with a liquid all-purpose cleaner;
2. dry sweeping dust and debris away from the side walls of the facility;
3. 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
4. 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:

1. 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;
2. A HEPA filtered vacuum was purchased for cleaning of the target area of the range; and
3. 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.

Industrial Hygiene Success Story

Case 3: Exposure Control of Softwood Dust in Manufactured Home Facilities

Presented at the AIHC 2002 Poster Session by Chris Collins, former Georgia Tech Consultation Program Staff Member

Abstract

Inhalation of excessive levels of dust may cause nasal dryness, irritation, nasal obstruction, coughing, sneezing, wheezing, and nose bleeding. Other effects of inhalation may include bronchial asthma, sinusitis, prolonged colds, and respiratory problems. Skin and eye exposure may lead to allergic contact dermatitis and eye irritation. Additionally, wood dust has been classified as a carcinogen to humans by the International Agency for Research of Cancer (IARC).

This case study details an attempt to control over exposure to wood dust in a manufacturing home facility. Cabinet and Counter Makers operating table saws had ranges of wood dust exposure between 6.8-11.7 milligrams per cubic meter (mg/m3) respectively. The American Conference of Governmental Industrial Hygienist (ACGIH) has recommended a TLV of 5.0 mg/m3 for softwood dust and a TLV of 1.0 mg/m3 for hard wood dust.

An exhaust hood was placed on the table saws in accordance with NIOSH recommendations. The hood serves as both a guard and ventilation for the saw. Employee monitoring after the addition of the ventilation reduced employee exposure to 2.9- 4.4 mg/m3 respectively.

Background

The manufactured home facility is a privately owned company which has more than 300 employees. The facility operates 24 hours a day, 7 days per week. The shift is typically 8 hours but can vary depending on the days workload. In the Cabinet and Counter Top Area four employees on first shift cut wood for cabinet and counter top assembly. The majority of the 8 hour shift is spent cutting wood with a small portion of the shift (less than 1 hour) stacking wood and transporting to other areas for assembly.

The type of wood varied depending on the type of counter top or cabinet being made however all the wood types used during the survey were soft wood. Initial monitoring indicated that employees were overexposed to wood dust. Ventilation in accordance with NIOSH approved methods were installed and the employees were monitored again.

Methods

Wood Dust
Time weighted averages were taken from 3 employees. Samples were taken in accordance with NIOSH method 500 and 600. Samples were taken before and after ventilation was installed.

Evaluation Criteria
OSHA does not have a PEL specific for wood dust. However the ACGIH has recommended a TLV of 5.0 milligrams per cubic meter (mg/m3) for softwood dust and a TLV of 1.0 mg/m3 for hard wood dust.

Wood Dust
Inhalation of excessive levels of dust may cause:

• Nasal dryness
• Nasal obstruction
• Coughing
• Sneezing
• Wheezing
• Nose bleeding
• Bronchial asthma
• Sinusitis
• Prolonged colds
• Respiratory problems

Skin and eye exposure may lead to:

• Allergic contact dermatitis
• Eye irritation

Additionally, wood dust has been classified as a carcinogen to humans by the International Agency for Research of Cancer (IARC).

Results and Discussion

Before ventilation was installed all three employees monitored were above the ACGIH TLV for wood dust:

After ventilation was installed all employee exposures dropped below the ACGIH TLV for wood dust:

Conclusions

The air sampling indicated that the addition of ventilation can serve both as a guard on the saw and as a simple and affordable method to help reduce employee exposure to wood dust.

Industrial Hygiene Success Story

Case 4: Industrial Hygiene Hazards at Georgia Mobile Home Manufacturers, 1990-2000

Scott E. Brueck, CIH, National Institute for Occupational Safety and Health, Cincinnati, Ohio

Art Wickman, CIH, Georgia Institute of Technology, Atlanta, Georgia

Abstract

The Safety and Health Consultation Program at the Georgia Institute of Technology provides free consultation to small businesses in Georgia. Between 1990 and 2000 industrial hygiene surveys were conducted at 10 manufactured home facilities in the state. Each facility had approximately 125 to 300 employees and typically operated one shift per day. Manufacturing activities included welding, woodworking, cutting drywall, use of pneumatic staple and nail guns, and other activities similar to those in residential construction.

Representative air sampling was conducted to measure employees’ exposures to wood dust, nuisance dust, metal fumes from welding, and methylene diisocyanate (MDI). Monitoring results revealed exposures to be in excess of the OSHA PEL and/or the ACGIH TLV for each of these air contaminants, except MDI. Of particular concern were exposures to welding fumes and manganese fume. Fifty percent of the welders monitored had exposures in excess of the TLV (5.0 mg/m3) for total welding fumes and 83% had exposures to manganese fumes which exceeded the TLV (0.2 mg/m3). Specific problems with the exhaust ventilation system in the woodworking and drywall areas, such as plugged exhaust ducts, were observed and likely contributed to excessive exposures in those areas.

Representative full shift noise monitoring indicated that more than 50% of the employees were exposed to noise levels greater than OSHA’s Action Level of 85 dBA and over 10% were exposed above the PEL of 90 dBA. Additional noise concerns included lack of proper hearing protection use, inadequate or no hearing conservation program, and leaking compressed air lines contributing to noise exposures.

Other problems identified at these facilities included inadequate safety and health programs such as hazard communication, personal protective equipment, respiratory protection, fall protection, and prevention of commonly occurring injuries.

Manufactured Housing in Georgia

• 50,000 Mobile homes built each year (15% of total nationwide)
• 20 manufactured home facilities
• Average cost per home: $28,800
• Provide over $2.7 billion to Georgia’s economy

Source: GA Manufactured Housing Association-1996

Background

• Comprehensive industrial hygiene surveys conducted at ten Georgia manufactured home builders between 1990 and 2000 under the OSHA-funded Georgia Tech Safety and Health Consultation Program
• 125 to 300 employees at each facility surveyed
• Each facility operated one shift per day
• 10 to 12 single-wide homes typically manufactured each day
• OSHA or NIOSH sampling methods used to collect representative personal samples
• Sample analysis conducted by Wisconsin Occupational Health Lab, Madison, WI
• LWDI Rates ranged from 0 to 29.7
• One Facility had 1227 lost days in 1994
• Most common injuries: Musculoskeletal related, punctures from nail and staple guns, lacerations, contusions

Wood Dust

 

Welding Fumes

 

Respiratory Protection Hazards

 

Fall Protection

 

Nuisance Dust

 

Noise

 

Other Common Hazards

 

Hazard Control Recommendations

 

Air Contaminant Control Strategies

• Use slitter (produces no dust) to cut large pieces of drywall instead of table saw
• Install local exhaust ventilation and equip hand tools with local exhaust
• Ensure proper function of existing exhaust ventilation system
• Position exhaust hoods close to source of dust generation
• Eliminate unnecessary bends in ducts
• Clean ducts regularly
• Wear appropriate respirators until controls reduce exposures

Noise Control Strategies

• Repair leaks in compressed air lines and implement preventive maintenance
• Install air diffuser mufflers on pneumatic tools
• Purchase staple and nail guns which generate less noise in future
• Purchase saw blades designed to minimize noise generation
• Enforce the proper use of hearing protection

Other Control Strategies

• Use mechanical lifting devices, two-person lifting, and other procedures to reduce musculoskeletal injuries
• Install sequential fire trigger mechanisms to reduce accidental firing and resulting puncture injuries
• Require and enforce the use of safety glasses and cut-resistant gloves
• Implement OSHA-required programs such as respiratory protection, hearing conservation, personal protective equipment, hazard communication and fall protection

Industrial Hygiene Success Story

Case 5: Control of Wood Dust During Manual Sanding

Michelle L. Dunham, MSPH
Art Wickman, CIH

Georgia Institute of Technology Atlanta, Georgia

Abstract

Woodworkers are routinely overexposed to wood dust when they use powered hand-sanding tools for the surface preparation of wood furniture. Exposure to wood dust causes nasal cancer in human, and other health effects including bronchial asthma, chronic bronchitis, hypersensitivity pneumonitis, and allergic contact dermatitis. Certain hardwoods, including those which are preferred in furniture manufacturing, appear to be associated with higher toxicity. In response to the research linking wood dust to adverse health outcomes, occupational exposure limits have been lowered. The current ACGIH TLV is 5 mg/m³ for soft wood dust, and 1 mg/m³ for certain hardwoods.

The current study documents reductions of exposures in two cabinet shops, which were surveyed to evaluate employee exposure to wood dust during the use of non-ventilated palm sanders. At one facility, two face frame sanders were evaluated and at the second facility three case sanders were evaluated. Samples were collected in aluminum-shielded cassettes on 5-micron PVC filters, using Gilair 5 sampling pumps at 2.0 LPM. Analysis was done at the Wisconsin Occupational Health Laboratory (WOHL) per NIOSH methods 0500/0600. Breathing zone concentrations for the face frame sanders and case sanders ranged from 16 to 107 mg/m3 and both the OSHA PEL (15 mg/m³) and ACGIH TLVs were exceeded. Both facilities changed to sanders with dust collection systems to reduce wood dust exposure. The follow-up exposure monitoring ranged from 1.4 to 10.7 mg/m3, a reduction of greater than 80%. Employee exposure to wood dust during hand sanding operations was substantially reduced. The controls used are readily available, and economically feasible. However, these effective controls are not in wide spread use.

Background

According to the 1999 US Bureau of Labor Statistics, an estimated 225,000 U.S. workers are employed in the manufacture of wooden cabinets and furniture. Among these workers, the highest exposures often occur when powered palm sanders are used for the final preparation of the wood surface.

Workers in furniture and cabinet shops often use palm sanders that lack dust control. For this type of sander, two forms of dust control are commercially available. For pneumatically driven units, models are available with a venturi fitting in the exhaust stream. As exhaust air passes through the venturi, a vacuum is created which is used to pull dust particles through holes in the face of the sanding pad and into an external filter bag. A second form of control, available for both pneumatic and electric tools, is a hood with an exhaust fitting which connects to an external vacuum source. The current study compares pneumatic sanders which were unventilated to pneumatic sanders which had an internal venturi-driven exhaust system. The wood species used in the study were a combination of both soft and hard woods.

Methods

Full-shift personal monitoring was conducted at two cabinet shops. At cabinet shop A, two face sanders were monitored and at cabinet shop B three case sanders were monitored. Samples were collected in aluminum-shielded cassettes on 5-micron PVC filters, using Gilair 5 sampling pumps at 2.0 LPM. Analysis was done at the Wisconsin Occupational Health Laboratory (WOHL) per NIOSH methods 0500/0600. All five employees were monitored using non-ventilated palm sanders and then using ventilated sanders. Cabinet shop A used basic sanders and cabinet shop B used deluxe sanders.

Results and Discussion

Both cabinet shops A and B reduced wood dust exposure by 85 to 97% after they replaced unventilated sanders with models which contained venturi-driven local exhaust systems. While these reductions were substantial, neither company achieved levels which met either the NIOSH REL or the ACGIH TLV of 1 mg/m³ for hard woods. This may be due to the weak vacuum induced by the venturi system. In a 1992 study, NIOSH measured this vacuum to be approximately 2 inches water gauge. (1) Since the sanders are spinning, they forcibly eject dust particles, and these particles likely escape capture by the weak vacuum of the venturi system. Thus, NIOSH recommended the use of a vacuum at 8 inches water gauge. In order to achieve higher vacuum pressure and lower exposure levels, an external central vacuum was required in the NIOSH study.

Conclusion

Palm sanders with internal, venturi-driven vacuum systems substantially reduced the exposures of employees to wood dust. Exposures were reduced below the OSHA PEL for nuisance dust of 15 mg/m³. These sanders are commercially available, economically feasible, and should be used to prevent overexposure to wood dust in cabinet shops. However, to achieve reductions to below the NIOSH REL or the ACGIH TLV¬ of 1 mg/m³ for hard woods, a larger vacuum source is needed.

Reference

1. Hampl, Vladimir; Topmiller, Jennifer L.; Watkins, Daniel S.; and Murdock, Donald J.: “Control of Wood Dust from Rotational Hand-Held Sanders”. Applied Occupational and Environmental Hygiene. 7(4): 263-270, (1992).