How air monitors prompted investigation into lead levels

The Michigan Department of Environment, Great Lakes, and Energy, Air Quality Division (AQD) has conducted air monitoring for lead near Mueller Brass Company since November 2012. Mueller is a brass foundry located in Port Huron. Lead is routinely used in the production of brass products.

Air monitoring staff have 48 monitoring locations through the state and over 100 separate air monitors measuring a variety of pollutants. The Port Huron area currently has two monitoring locations.

EGLE's Air Quality monitoring staff collect special lead filters from the air monitoring unit and conduct quality assurance checks each month. The equipment that collects the air samples is a small unit like the one at left. The unit was placed north west of the Mueller Brass facility on Rural Street. Every six days, air is pulled through a filter for 24 hours. The filter is removed from the sampler and sent to the EGLE Laboratory for analysis. The analysis measures lead as well as manganese, arsenic, cadmium, and nickel.  

Ensuring the public is protected from potential health impacts related to lead exposure is very important. As it relates to lead, the United States Environmental Protection Agency has developed a National Ambient Air Quality Standard. Measurement against this standard is based on a 3-month rolling average value. AQD monitoring staff became concerned when the 3-month rolling average being observed at the Port Huron air monitor had higher than normal levels. Although the lead being measured did not surpass the standard for lead for the 3-month rolling average, there were spikes in the data over the standard. AQD monitoring staff informed the AQD inspector assigned to Mueller about the elevated lead levels and an investigation into the reason for the spikes began.

The AQD inspector talked with Mueller about the elevated levels of lead being observed. Mueller conducted their own look into the process and found baghouse malfunctions were the likely cause of the elevated lead levels. The inspector conducted a comprehensive inspection at the facility on  April 2, 2018  to determine the causes of the increasing trend. During the inspection, the inspector walked through a plant environment (see photos below) with poor visibility.

The inspection and subsequent records review revealed a number of violations regarding proper operation of the baghouse. Violation Notices were issued to Mueller on  April 17, 2018  and on  May 15, 2018 .

On May 17, 2018, the baghouse had another malfunction. This malfunction was reported to the AQD by Mueller. Around the same time, the AQD recieved complaints about fallout (or dust) on a residents property. The complaints were investigated, samples were taken of the dust as well as the material in the baghouse at Mueller. These samples were sent for analysis. Once received, the samples were determined to be statistically similar. An additional Violation Notice was issued on  June 29, 2018 .

Once a Violation Notice is issued, the facility must develop a plan to return to compliance and then must implement the plan to the satisfaction of EGLE.

As a result of AQD's investigation, the company replaced a baghouse, re-evaluated and implemented comprehensive Preventative Maintenance and Malfunction Abatement Plans for the equipment. These plans are an enforceable part of a permit and lay out specific parameters the equipment must meet. Additionally, Mueller performed  stack testing  to ensure proper operation of the equipment as well as to demonstrate emission limits are being met.  

Once these actions were complete, the measurements of lead from the air monitor were significantly reduced.

On  July 16, 2019 , the inspector conducted a follow-up inspection of the facility. Facility operations were much improved with the new equipment installed and operating properly.

Additionally, lead levels measured at the air monitor were greatly reduced and spikes in lead emissions are no longer being observed. Mueller entered into a legally binding  Consent Order  with EGLE and paid a fine of $60,260.00 due to the severity of the violations.

Throughout the process, EGLE's AQD staff engaged the help and expertise of other EGLE Division staff, the Michigan Department of Health and Human Services, and the St. Clair County Health Department staff. Partners helped to investigate lead levels in soils around residential areas, conduct blood level lead testing of residents and employees of Mueller as well as to help communicate possible risks to the public.

As EGLE values communication and serving the public, EGLE staff will continue to monitor air quality in the areas around Mueller and ensure lead levels stay below the National Ambient Air Quality Standard. EGLE will also continue to work to ensure compliance with applicable rules and regulations to protect future generations.