A painted exposure issue
An employee in the work place voice her concern about the smell of paint fumes. Her work station was in the shipping dock. That work station was about 80 feet away from two small paint booths in the building. Part of her duties caused her to move about the manufacturing plant.
Paint fumes can drift and the concern was that this employee felt light headed at times. The employer, out of an abundance of caution requested air sampling be conducted.
I conducted a walk-through of the site and spoke with several management and employees around the plant to determine their input on about the paint process. Two painters used two different paint booths. Both paint booths were equipped with air extraction ventilation units, and each booth also had large filtration screens attached within the booth area. The two painters were equipped with SAR (Supplied air respirators) as well as they used tyvek full body coverings. The painters painted with air powered paint guns in the booths.
One of the painters also often performed touch up painting outside about 70 feet from the shipping dock. Touch up involved small can and brush painting to fill in small unpainted gaps. The use of 100% MEK (methylethyl-ketone) was used to clean the surfaces before touch up on products.
I conducted an examination of the paint used in the processes and found two main paints being applied. The two paints were studied by using their Safety Data Sheets. It was determined that each paint had 6-7 constituent chemical components. The paints shared in common many of the same constituents. A study of the chemicals determined both their concentration, air density and their OSHA rated Permissible exposure levels (PEL).
Based on the gravity of the constituent's PEL, percentage volume in the paint and the air density, I determined to test for 5 specific constituents. The major component in the paints were MEK, DMEA, n-butyl acetate, ethyl acetate, and MIK(methly iso-butyl ketone). It is imperative that when we have numerous organic compounds that we test for the cumulative impacts of each to determine the exposure upon the workforce.
I selected five air sampling targets; Two painters, one shipping clerk, one static test station at the shipping clerks area, and one static test station at the painting area. The painter was tested such that one was working in the paint booth, while the other was working on touch up across the plant.
The results: The predominate low density target was the MEK, that constituent had the most presence in the paint and the lowest air density making it lighter in air and the most likely fume being detected by workers. The other constituent's results were all 'less than', meaning so low as not to be harmful or noticed.
MEK; The PEL of MEK is 200 ppm (part per million) The results were: The painter in the booth was 247 ppm, painter in the plant doing touch up was 37 ppm, the shipping area was .27 ppm and the employee working in shipping and walking around that day was .33 ppm
Conclusion: The painter in the booth using SAR protection was protected above 5000 ppm, same as the painter doing touch up. No employee was ever exposed to any harmful level of paint fume. The employee concerned about smelling paint likely smelt a pocket of air that quickly resolved. The percent of likely exposure was .165 % of the PEL for MEK.
Recommended actions: Ensure use of local air fans in the paint department and shipping dock. Ensure MEK can is covered at all time when not in use and covered when not dipping the brush when doing touch up. Communicate findings of the air sampling to ensure employees that the levels of paint fumes tested were well below the OSHA PEL.