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Jonathan Modie
OHA External Relations 971-246-9139
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3/1/2017

Public comment sought on new 24-hour screening levels for air toxics

Review process moves to next phase after evaluation by outside toxicologists

PORTLAND, Ore.—The Oregon Health Authority and the Oregon Department of Environmental Quality are seeking public comment on an updated list of concentration guidelines for assessing immediate risks from certain air toxics.

The public comment period for the new short-term guideline concentrations (SGCs)—referred to as “24-hour screening levels”—for 15 air toxics is the next phase in re-evaluating these concentration limits. The agencies developed the proposed guidelines with consultation and rigorous technical review by toxicologists inside and outside the agencies, between October 2016 and January 2017.

The SGCs will replace and expand upon the provisional 24-hour screening levels for metals that OHA issued in March 2016. The expanded list of 15 air toxics goes beyond metals discovered in air emissions from companies in Portland, and includes additional air toxics of potential short-term concern around the state, including naphthalene and hydrogen sulfide.

“It’s very important to the agencies that short-term guideline concentrations are based on the best available science,” said David Farrer, Ph.D., toxicologist with the OHA Public Health Division’s Environmental Public Health Section. “This robust scientific review of screening levels will help our agencies accurately interpret ambient air monitoring data to ensure protection of public health.”

The “Proposed Short-Term Guideline Concentrations” are posted at the Cleaner Air Oregon website. Public comment on the document will be open through March 31, 2017. Comments can be submitted to EHAP.Info@state.or.us.

OHA developed the original provisional set of 24-hour screening levels in March 2016 in response to intense community concern about emissions from art glass manufacturers Bullseye and Uroboros. The 2016 values used the most stringent health-protective values agency toxicologists could find from peers in other states at the time.

External scientific peers with expertise in toxicology have reviewed the proposed updated SGCs, and their comments have been incorporated in the draft now being presented for public comment.

The current list of SGCs includes arsenic, beryllium, cadmium, total chromium, chromium +3, chromium +6—also known as hexavalent chromium—lead, manganese, nickel and selenium. The proposed new list includes these metals and adds acetone, hydrogen sulfide, methyl ethyl ketone (MEK), naphthalene and styrene.

The new list excludes cobalt, since air monitoring data showed it never exceeded the old 24-hour screening levels and external scientific peer reviewers expressed concerns about the strength of the science supporting a short-term toxicity value for cobalt.

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