Note: Martin’s 2004 recommendation to follow American dental hygienists’ threshold limit of 25 µg/m3 per 8 hours exposure contradicts the Chippewa County Health Departments 1991 recommendation to follow EPA threshold limits: “[Hesse] agrees that the EPA’s recommendations should be followed along with employee urine testing as recommended by the Chippewa County Health Department.”

Note: EPA recommendations:

Employees working inside buildings with mercury spills should be aware of the Environmental Protection Agency’s (EPA) precautions on “sick building syndrome” for chronic exposure to indoor mercury vapor ( See the EPA’s “Indoor Air Pollution: An Introduction for Health Professionals”.) “The EPA sets a reference concentration of 0.3 µg/m3 for inhalation exposure to mercury. For example, if 0.3 µg/m3 mercury was measured in air inside a building, EPA would further investigate the exposure. … The Agency for Toxic Substances and Disease Registry has set a minimal risk level (MRL) for inhalation exposure at 0.2 µg/m3. The MRL is an estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse health effects over a specified period of time.” (From newmoa.org)

Note: GLSHS employees exposed to the 1989 & 1991 mercury spills at Whitefish Point were never tested for toxicity. A seemingly disproportionate number of long-term employees of the Shipwreck Museum have suffered from dementia.  American dental hygienist's standards should NOT be used for GLSHS employees.

- WPPS Steering Committee