Hibbing Public Utilities notifies residents after lead action-level exceedance; MDH, utility outline testing and replacement steps

Hibbing Public Utilities told the public on Oct. 28 that compliance sampling taken between June and September produced a lead action-level exceedance under the federal lead-and-copper rule. Minnesota Department of Health compliance engineer Hannah Mendez said Hibbing collected 29 required lead samples and that six of those samples were above the action level, causing the system's 90th percentile to exceed the Environmental Protection Agency's action level of 15 parts per billion.

"It does not mean that every tap in the community that is used for drinking water has elevated levels of lead, but it does mean that the system has to let the residents know that they are investigating the cause of the elevated lead levels and are taking actions as necessary to evaluate the lead levels," Mendez told the commission and the public during a special presentation at the Oct. 28 meeting.

MDH and Hibbing staff outlined immediate and near-term steps required by law and agency guidance. MDH notified Hibbing of the exceedance on Oct. 20; the utility said it issued a public notice within 24 hours and is working on additional public education materials and a QR link to MDH resources. The utility must also perform additional sampling to better evaluate lead levels, test source water to confirm the aquifer is not the source, and assess corrosion-control treatment at the water treatment plant.

Hibbing staff said they are evaluating corrosion-control additives at the treatment plant and working with engineering consultants to seek MDH approval before implementing any chemical changes. Utility staff emphasized, however, that the plant project currently under construction has not been placed into operation and therefore is not the cause of the exceedance.

The utility is expanding its service-line inventory and conducting field work to identify buried materials. Staff said roughly one-third of the city's system had been identified in the inventory to date and that the statewide inventory for Hibbing includes about 5,600 service connections: "over 3,300 are known non-lead" and about 2,300 remain listed as unknown. The utility said it has replaced 23 known lead service lines and has three more replacements planned for this year. Staff noted the city received approximately $1 million in state funding last year to support inventory work and service-line replacement.

Field work described at the meeting includes potholing at curb stops using a vac truck so crews can see pipe material on both the private (house-side) and public (utility-side) of the curb stop. Staff said private-side materials are more often identified because they are accessible; public-side materials remain buried and require excavation.

MDH and the utility provided residents with steps to reduce potential exposure: use cold water for drinking and cooking, let cold water run before use, regularly clean faucet aerators, use a filter certified to remove lead, and consider having household water tested. MDH's blood-lead surveillance supervisor, Stephanie Bridal, said the system actions being taken do not, by themselves, create a new requirement for blood-lead testing beyond existing pediatric screening recommendations at ages 1 and 2; parents concerned about specific children should consult their pediatrician.

Utility staff asked homeowners to schedule interior inspections when their service-line material is listed as "unknown" in the statewide inventory so the public- and private-side materials can be resolved. Staff also said replacement work under the current program will be done under the utility's existing construction contract and homeowners will be notified and scheduled if a replacement is required.

The utility and MDH urged residents to use the statewide service-line inventory mapping to see whether their address is known, to participate in inspections, and to take the listed precautions while the utility performs follow-up testing, corrosion-control evaluation and prioritized replacements.