An estimated 3,000 people attended and more than 1,000 participated in the cheer, dance and drill competitions sponsored by Washington Interscholastic Activities Association.

The illnesses may be caused by several viruses and bacteria that may come from a wide variety of sources, health officials said

Symptoms include nausea, vomiting, diarrhea, and may also include headaches, stomach cramps, and fever.

Good personal hygiene including frequent hand washing can help prevent the spread of disease, officials said.

The cause and specific disease are still under investigation, officials said, people who attended the event and have severe symptoms are advised to contact a health care provider.

Carbon monoxide poisoning can kill you. Carbon monoxide gas comes from burning fuels such as gasoline, propane, oil, kerosene, natural gas, coal or wood.

Prevent poisoning from carbon monoxide:

• Only use a generator outdoors and far from open windows and vents

• Never use a generator or portable propane heater indoors, in garages or carports

• Never cook or heat inside on a charcoal or gas grill.

Carbon monoxide poisoning can happen suddenly and without warning. Physical symptoms of carbon monoxide poisoning may include splitting headache, nausea and vomiting, and lethargy and fatigue.

If you believe you could be experiencing carbon monoxide poisoning, get fresh air immediately. Call for medical help from a neighbor’s home. The Fire Department will tell you when it is safe to re-enter the home.

For a full list of carbon monoxide prevention tips and other safety and disaster information in English and other languages, visit www.kingcounty.gov/health/disaster

If you have a power outage, use safe ways to stay warm:

• Find places where you can go to get warm, such as the home of friends and family whose homes have power. Many cities have opened centers where people can go during the day to stay warm. Center locations can be found at www.kingcounty.gov/safety/prepare

• Wear several layers of light weight, warm clothing rather than one layer of heavy clothing. Wear hats, mittens, and blankets indoors.

• Close curtains and cover windows and doors with blankets. Everyone should try to stay together in one room, with the door closed, to keep in body heat.

• Check on elderly friends, family, and neighbors to make sure they are safe.

• Watch your footing on surfaces that may be icy and slick, and wear shoes that provide traction.

• Be careful not to overexert yourself when shoveling snow, especially if you have heart disease or high blood pressure, as the cold weather puts extra strain on your heart.

• Do not sled on streets or on slopes near streets, ponds, or streams.

• Avoid driving if you can. If you must drive, allow safe stopping times and distances.

• Warn others about carbon monoxide poisoning. Share the information with neighbors, friends, family and community groups.

• Check on family, friends, and neighbors, especially if they are elderly or if you think their power might be out.

• If you know someone who has lost electricity, invite them to your home to stay warm.

If power goes out where you live, keep food safe:

• Keep the doors closed on your refrigerators and freezers as much as possible. This keeps the cold air inside. A full freezer can stay at freezing temperatures about two days; a half-full freezer about 1 day.

• If you think the power will be out for several days, try to find some ice to pack inside your refrigerator. Keep raw foods separate from ready-to-eat foods.

• Refrigerated foods should be safe as long as the power is out no more than a few hours and the refrigerator/freezer doors have been kept closed. Throw away foods that spoil easily (such as meat and fish) if they warm up above 41º F.

• Frozen foods that remain frozen are OK to eat. If potentially hazardous foods are thawed (such as meat and fish), but are still cold or have ice crystals on them, use them as soon as possible. If potentially hazardous foods are thawed and are warmer than 41º F, throw them away.

Each year in Washington, dozens of people get sick and die from carbon monoxide poisoning. And many are hospitalized for carbon monoxide exposure. During power outages, carbon monoxide poisoning is a major concern when people use charcoal briquettes or generators indoors as a heat source.

Fast facts about carbon monoxide:

• Carbon monoxide is a poisonous gas that can’t be seen or smelled.

• Carbon monoxide is produced whenever any fuel such as gas, oil, kerosene, wood, or charcoal is burned.

• Carbon monoxide builds up so quickly that people are overcome before they can get help.

• It can kill a person in minutes.

Every home should have a carbon monoxide detector to warn families when carbon monoxide levels become unsafe, health officials say, and if the alarm sounds, you should get outside to fresh air immediately.

Sources of carbon monoxide include blocked chimney flues and gas or kerosene heaters used indoors. Never burn charcoal in a fireplace, health officials warn.

For a list of sources of carbon monoxide go to: www.doh.wa.gov/ehp/ts/IAQ/co_fact_sheet.htm

An attached garage is a part of your home; carbon monoxide fumes can seep-in from generators or idling cars and from outdoor generators placed too close to open windows or vents, they add.

To learn more:

• The state Department of Health has a fact sheet on preventing carbon monoxide poisoning (www.doh.wa.gov/phepr/handbook/co.htm) during a power outage; it’s available in multiple languages.

• The agency provides a wide range of emergency preparedness information (www.doh.wa.gov/phepr/default.htm) from earthquakes to windstorms available in our Emergency Resource Guide(www.doh.wa.gov/phepr/handbook.htm).

Photo: Sanja Gjenero

The  Puget Sound Clean Air Agency has issued a Stage 1 burn ban for King, Kitsap, Pierce and Snohomish counties, as a high-pressure system brings cold temperatures and calm winds to the region and creates conditions that can trap smoke from wood fires and other air pollutants.

Under the ban the use of fireplaces and uncertified wood stoves is prohibited until further notice.

Air quality is expected to worsen at least through Friday, especially in communities where residential wood burning is common, Clean Air Agency forecasters said.

Air pollution can trigger asthma attacks, cause difficulty breathing, and make lung and heart problems worse.

Air pollution is especially harmful to people with lung and heart problems, people with diabetes, children, and older adults (over age 65), the agency warned.

The Washington State Department of Health recommends that people who are sensitive to air pollution limit time spent outdoors, especially when exercising.

Photo by Sanja Gjenero

During a Stage 1 burn ban:

• No burning is allowed in fireplaces or uncertified wood stoves. Residents should rely instead on their home’s other, cleaner source of heat (such as their furnace or electric baseboard heaters) for a few days until air quality improves, the public health risk diminishes and the ban is cancelled.The only exception is if a wood stove is a home’s only adequate source of heat.

• No outdoor fires are allowed. This includes recreational fires such as bonfires, campfires and the use of fire pits and chimineas.

• Burn ban violations are subject to a $1,000 penalty.

It is OK to use natural gas, propane, pellet and EPA certified wood stoves or inserts during a Stage 1 burn ban.

(Note: The Seattle Parks Department prohibits beach fires at Alki and Golden Gardens during air quality burn bans.)

How to tell if a wood stove is certified, and OK to use during a Stage 1 burn ban?

Age matters – if the stove is over 20 years old, it is likely uncertified and prohibited for use during a burn ban.  Uncertified wood stoves are no longer legal to sell or purchase in the State of Washington due to the significant pollution they generate.  A certified stove will have an EPA label on the back.

For more information:

• Updated air pollution data and forecasts

• Frequently asked questions about burn bans

November through March winter weather often causes stagnant air that traps air pollution from outdoor burning, wood stoves, and fireplaces gets trapped near the ground, officials said.

Who is at highest risk?

Breathing polluted air can cause short and long-term health problems. People with heart and lung diseases are more likely to develop serious health problems. Sometimes, older adults have heart or lung disease that they’re not aware of, and it puts them at risk. Kids spend more time outside, where they’re exposed to air pollution for longer periods. Children’s lungs are more easily damaged because they’re still developing.

Exercise and air pollution:

When air quality is poor, people should limit outdoor activities and reschedule them for a time when air quality is better. When people exercise, they breathe more air and air pollution into their lungs. If you decide to exercise, choose a less strenuous exercise such as going for a walk instead of a run. And avoid exercising in higher pollution areas such as near highways or in neighborhoods with a lot of wood smoke.

How to check air quality

Be sure to check air quality (http://www.airwatchnw.org) before heading out for outdoor activities, especially if you’re in a high-risk group. Often air pollution can’t be seen or smelled, so it’s hard to judge air pollution levels.

Burn bans:

Several burn bans have been issued across the state recently because of poor air quality. Smoke contains fine particles and toxic gases that can be breathed deep into lungs. Some counties in the state are under a burn ban. Before you burn, check to see if your county is under a burn ban (www.waburnbans.net).

To learn more:

• More information about how air quality can affect your health (www.doh.wa.gov/ehp/smokefactsheet.pdf) is on the Department of Health website.