The Portland Fire Bureau and Portland police are responding to the report of an

leak at the

, 6149 S.W. Shattuck Road.

Officials are advising residents to

, keeping windows and doors closed and staying inside until the all clear is given.

Residents between the boundaries of Southwest Oleson Road to the west of the dairy, Southwest Shattuck Road to the east; Southwest Vermont to the south; and Southwest 55th Avenue to the north are in the affected area.

Tim Donovan, a spokesman for the Portland Fire Bureau, said Alpenrose Dairy officials reported a broken valve in one of their technical rooms. Ammonia is used for cooling dairy products, he said.

"We're asking residents to tune in their radios and TVs for updates and to close their ventilation systems,'' Donovan said.

Marcia Miller, who lives about 200 yards from Alpenrose's large complex, brought her dog and cat inside when she saw reports of the leak on the noon TV news.

"I stuck my nose out and could not smell anything,'' Miller said.

She said she was expecting a reverse 9-1-1 call advising her to shelter in place, but no such call came.

Officials on the scene said winds were blowing about 6 mph from the southwest.

The fire bureau is setting up a Haz-Mat command post on the north side of the dairy in a parking lot, Donovan said.

Around 12:40 p.m., fire officials were suiting up in Haz-Mat suits and will enter the building with a photograph of the valve, which is not damaged but merely on and leaking the ammonia into the building.

Police are also shutting down roads near the site of the leak. Fire officials said there are no immediate reports of anyone being harmed by the leak, and that all dairy employees are out of the building and unharmed.

According to the

ammonia can cause a b

urning sensation in the throat, coughing, labored breaking, sore throat and shortness of breath. Symptoms may be delayed

after exposure.

What does shelter in place mean?

Here's what the Portland Fire Bureau advises:

Shelter: Go inside your home or the nearest building. Choose an inside room with as few windows or doors as possible. Bring in pets, if possible. Shut: Shut and lock all windows and doors to create a better seal. Turn off the heater or air conditioner. Make sure the fireplace damper and all ventilation fans are closed. If you are told there is danger of explosion, close the window shades, blinds or curtains. Listen: Local officials are your best source of information. Keep listening to your radio or television until you are told it is safe to leave the shelter or to evacuate. When you leave the shelter, follow instructions from local officials to avoid any harmful materials outside. Do not use the telephone unless you have a life-threatening condition to keep lines free for emergency responders.