SOUTH SIOUX CITY, Neb. (AP) — A city administrator says a company is taking steps to eliminate a horrible odor that’s some residents say has forced them to temporarily leave their South Sioux City neighborhood.

The odor primarily has affected 15 houses in a five-block area where about 40 people live. City Administrator Lance Hedquist said Monday the odor originates at the Big Ox Energy plant about two miles away. He says sewage from the homes and the plant meet at a lift station that sends the sewage to the sewer plant.

Hedquist said Big Ox intends to begin adding to its sewage outflow a chemical that should end the problem.

Denmark, Wisconsin-based Big Ox converts organic waste into methane gas. A company spokesman didn’t immediately return a call from The Associated Press.