An air quality bill passed by the Iowa House of Representatives last week is drawing both criticism and praise.

The bill sets a limit to the emissions level of hydrogen sulfide deemed safe for the environment and human health.

Hydrogen sulfide is a colorless gas with a rotten-egg odor at low concentration levels. Different levels of exposure to the gas causes different health problems ranging from dizziness and nausea to convulsions and death.

Rep. Mark Kuhn, D-Charles City, opposed the bill, calling it “a right to pollute law,” because all industries — not just the livestock industry — will be able to emit large amounts of hydrogen sulfide.

Kuhn said it will be difficult to monitor levels of hydrogen sulfide exceeding the set levels due to varying wind directions in Iowa. The bill also prohibits Iowa from imposing standards stricter than national standards.

“The vast majority of family farms are doing a good job of protecting air quality, and they don’t need the leniency of this bill,” he said.

Under the bill, it will take five years for a producer emitting questionable levels of hydrogen sulfide to be penalized, Kuhn said.

Monitoring units are placed too far from livestock operations, and the effects of hydrogen sulfide have not been tested enough in recent years, he said.

Rep. Sandy Greiner, R-Keota, introduced the bill. She said she predicts mid-sized producers who contract out hogs and also work off the farm will encounter the biggest problems if the legislation is passed into law.

“[That’s] because [they] don’t have all day to address the issues,” she said.

Large-scale producers have enough time and employees to handle emission problems as they occur, Greiner said.

Greiner looks to the future of new and experimental techniques to solve the issues of hydrogen sulfide and ammonia emissions.

“In my heart I know in the end they’re going to figure out how to do this in the gut [of the hogs] through feeding. The question is, can they figure it out before all the mid-sized guys are gone?”

Research for the bill, HR 2523, states hydrogen sulfide must reach a level of 70 parts per billion (ppb) for 14 consecutive number of days before it is considered an acute health problem, Greiner said.

To be an intermediate health problem, levels must reach 30 parts per billion for up to 364 consecutive days.

Catharine Fitzsimmons, chief of the Iowa Department of Natural Resources’ Air Quality Bureau said her group opposes the bill.

The DNR is recommending the standard be set at 15 parts per billion concentration for one hour. She said the concentration level could be exceeded seven times with the eighth time being a violation under their recommendation.

Greiner said the department’s suggestion was overzealous.

“Its an attempt from the DNR to file rules that [would be] so stringent you couldn’t keep a kitty-litter box,” she said.

Dwaine Bundy, professor of agriculture and biosystems engineering, has researched hydrogen sulfide. Monitored levels of the gas are almost always below standards set by the house bill, he said. He said he supported the science behind the bill.

Although the livestock industry is affected by the bill, the bill is not a livestock production odor issue, Bundy said.

“There is a misconception that whenever you observe an odor down wind from livestock it’s hydrogen sulfide,” Bundy said.

This is not the case because most other compounds, chemicals and gas molecules create or emit odors, he said.

“We want to call a spade a spade,” Bundy said.

“If its an odor issue it’s an odor issue. If it’s a health issue, it’s a health issue.”