Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
1 · 2 · 3
July/August 2009
Howard Rosenberg,
University of California, Berkeley
igh temperatures and the rush of summer activity increase risks of heat-related problems. Heat can cause plenty of harm short of fatality, and not only in warmweather seasons. It is a fact of life in vineyards across the nation.
In California, grape growers and workers face legal as well as physical heat-related challenges. A state regulation designed to reduce the risks of heat illness in outdoorworkplaces took effect inmid-summer 2006, adding to employers’ responsibilities for safe operation.
The rule obligates all covered employers, including vineyard operators, to take specific measures to help workers control heat stress and get timely care for heat-related illness. (See Basics section, page 90). It carries significant penalties for noncompliance.
During the 2009 mid-May heat wave, the California Division of Occupational Safety and Health (Cal/ OSHA) shut down eight farm labor contractors in the central and southern valleys for violations of the heat illness prevention regulation. Charges included not providing adequate drinking water or shade for employees working in very high temperatures.
Cal/OSHA can stop operations with an Order to Prohibit Use (OPU) when it finds workers exposed to an imminent hazard, until it is satisfied that the employer is ready to safeguard them. The first three OPUs in heat-related cases were issued in 2008.
Regardless of legal mandates, it pays to help workers minimize heat stress impacts. But following rules, keeping the Igloos® full, having shade nearby, and reciting a litany of
advice to drink lots of water, beware of stress symptoms, and rest when necessary goes only so far.
How heat hurts
Humans can perform work under a wide range of conditions as long as their internal organs and biochemical reactions are doing well, which depends on their temperature being within a narrow range around 98.6ºF. When bodies get too cool or warm, natural processes that add or release heat kick in to restore the norm.
Although “feeling hot” causes discomfort and distraction, the cooling process often gives rise to greater dangers.While heat stress tends to be more of a problem when the weather is hot, high ambient temperature is not its primary cause.
Heat from solar radiation and surrounding air can affect vineyard workers butmost of the heat that they have to cope with is producedwithin their own bodies. The body’s metabolism generates some heat even at rest.When it speeds up during physicalwork, its yieldof heat as a byproduct also increases.
This heat raises internal temperature, threatens normal functioning, and triggers dissipation mechanisms. Internally generated heat is more difficult to release where the air is hot, humid, or still. Both retained heat and the body’s attempts to shed it can eventually cause symptoms recognized as a “heat illness” that impairs physical or mental activity, reduces performance, increases risk of accidents, and endangers life. Heat stroke, themost serious such illness, is amedical emergency.
Although less critical ailments — heat exhaustion, heat syncope (fainting), heat cramps, and heat rash — are not immediately life-threatening, they reduce well-being and performance and can progress to heat stroke if not treated. The sidebar describes common symptoms of and treatment guidelines for these illnesses.
Even minor effects of excess body heat and the loss of fluid through sweating may cause damage.
Subtle discomfort, weakness, blurred vision, slowed reactions, diverted attention, lapses in concentration or judgment, reduced coordination, and irritability add to chances of workers hurting themselves and also translate into higher production costs. Heat stress is probably under-credited as a factor contributing to workplace accidents.
Heat Illness Symptoms and First Aid
HEAT RASH – Acute skin inflammation and clogging of sweat ducts. Regarded as the least severe of heat illnesses. Though it usually causes only temporary discomfort, it can lead to a bacterial infection that shuts down the function of sweat glands. Rx: Cleanse the affected area thoroughly and dry completely. A mild steroid cream, calamine, or other soothing lotion may help relieve discomfort and infection.
HEAT SYNCOPE – Loss of consciousness, generally sudden, due to lack of sufficient blood and oxygen to the brain. Greatest danger is secondary injury from a slip or fall. Most likely to affect people not yet acclimatized to work in hot environments. Heat stress can cause syncope by diverting blood to extremities or lower body at the expense of the brain. Rx: Rest, ventilate, and drink plenty of water or electrolyte fluids.
HEAT CRAMPS – Painful, involuntary muscle contractions – most common in calves, thighs, arms, and abdomen -- heavy sweating, and thirst. Often extremely uncomfortable and can be completely disabling. Typically occur during or after hard work and are induced by electrolyte deficiencies that result from extended periods of intense sweating. Rx: Rest and
drink plenty of water or electrolyte fluids.
HEAT EXHAUSTION – Symptoms include fatigue, headache, dizziness, muscle weakness, nausea, and chills, tingling of hands or feet, confusion, loss of coordination, fainting, and collapse. Occurs during exertion and results from dehydration, lack of acclimatization, reduction of blood in circulation, strain on circulatory system, and reduced flow of blood to the brain. Rx: Rest in the shade or a cool place. Drink plenty of water (preferred) or electrolyte fluids.
HEAT STROKE – The most extreme consequence of uncontrolled heat stress, a medical emergency that can develop suddenly from an untreated condition of heat exhaustion. Skin is hot and dry, body is typically hotter than 104°F and no longer able to cool itself, and themind is confused, delirious, or convulsive. Brain damage and death may result. Rx: Summon aid. Immediately move to the coolest place available, loosen clothing, fan and douse or spray the body continuously with a cool liquid. Begin to replenish body fluids by drinking. Get medical attention and/or transport to a medical facility as soon as possible.