GWH Blog

Winery Safety: Confined Spaces

E mployers, including those in the wine production industry, must be aware of the dangers their employees may face when entering confined spaces. OSHA, the Occupational Safety and Health Administration, has developed preventative measures and regulations to protect employees. Following is an overview of confined spaces, examples of confined space dangers within wineries, and an overview of OSHA’s general requirements.

What is a Confined Space?

A confined space is defined by several characteristics, three of which are:

1. The space must be large enough for a person to enter and perform job duties.
2. The space will also have restricted access to enter and/or exit.
3. The space is not designed nor intended for continuous employee occupancy.

Employers and employees must be aware that “entry” into a confined space is classified as any part of the body (including extremities) breaching the plane of the space.

Another type of confined space is a permit-required confined space. This space requires that a permit be filled out before entering a specific area in order to evaluate the conditions of the space and to allow safe completion of the work involved. A confined space requires a permit if at least one of the following characterizations is true:

1. The space contains, or may potentially contain, a hazardous atmosphere.
2. The space contains material with the potential for engulfment.
3. The space is constructed so that an entrant may potentially be trapped or asphyxiated.

The California Division of Occupational Safety and Health (Cal-OSHA) is responsible for overseeing and enforcing workplace safety standards throughout the state. Wineries are subject to guidelines put in place by OSHA and must comply with these regulations in order to prevent citations and, most importantly, to promote employee safety. The average cost of an OSHA citation is around $7,000 per infraction. With one or even multiple infractions, this quickly becomes needlessly costly for a winery and is absolutely preventable. Cal-OSHA outlines its regulations for Permit Required Confined Spaces under section 5157 and 5158 of California’s General Industry Safety Orders.

How Can Confined Spaces be Dangerous in the Winery?

As outlined above, there are several dangers to be mindful of when working with confined spaces. The most common scenarios for confined space entry in a winery occur during crush season with the increased usage of fermentation tanks and press equipment (Pregler B. 2009). A permit-required confined space may contain a hazardous atmosphere due to the displacement of oxygen by grape fermentation byproducts during the fermentation process, when sugar is converted into water, alcohol and carbon dioxide.

Carbon dioxide is a colorless, tasteless and odorless gas. In fact, people typically are not aware they have been exposed to carbon dioxide until the symptoms of toxicity have appeared. Because carbon dioxide is much heavier than air, it easily displaces oxygen. If the atmosphere is not monitored regularly, carbon dioxide may pose a serious threat to employees. The following table outlines the effects of carbon dioxide exposure in varying concentrations:


Another hazard when working with fermentation tanks during crush season is engulfment. Engulfment occurs when a person is overcome by a liquid or flowing solid, which may result in death. Employees must take the proper precautions when working in a confined space, such as a tank where grapes or grape skins are present, to avoid becoming engulfed. As discussed earlier, carbon dioxide is released into the air as grapes are fermented. A potential hazard may occur if an employee who is performing a “dig-out” (shoveling grape skins out of a fermentation tank) is unexpectedly exposed to dangerous levels of carbon dioxide within the tank. The employee could slip or fall, rapidly become unconscious, and consequently become engulfed.

Entry and Retrieval Systems

For these and other possible dangers, OSHA requires that the atmosphere of a potentially hazardous confined space be tested prior to entry. There are a number of options available for atmospheric monitoring. One accurate and relatively inexpensive method is to use a hand-held meter with an integrated alarm system. These hand-held devices are portable and can reliably alert employees to hazardous atmospheric environments. If the entry test indicates an unsafe atmospheric condition, there are some options that can be used to resolve it:

1. Simply wait longer and test again.
2. Set up a fan to blow over the top of the tank to increase airflow and achieve a more stable environment in a shorter amount of time.
3. Use a confined space fan in the tank.

Whichever route is used is likely to be time dependent. Any and all options would be good to use. The bottom line is, if the atmospheric test comes back as dangerous, DO NOT ENTER THE TANK!


Meter for Measuring CO2 Levels

What are the Regulations?

While there is no official list of regulations, wineries typically create their own procedures that employees must follow to work in the cellars. These procedures can include:

1. Communication: Employers must inform employees of all the permit-required spaces.

2. Written Program: Employers must develop a written confined space entry program that identifies and evaluates the confined space hazards as well as the procedures involved in safe entry, operations and what to do in case of emergency.

3. Training: Employees must be properly and routinely trained for the designated roles involved in confined space entry, including entrant, attendant, supervisor, and rescuer.

4. Retrieval System: Facilities must possess a retrieval (rescue) system to implement if an employee were to become incapable of self-rescue. (Rescue through these systems is preferred over rescue by another entrant such as the fire department because they may easily succumb to the same dangers, thus further escalating the problem.)

Ultimately, the cellar working environment is often full of activity, especially during crush season. Employers, employee and guests alike must be mindful of potential hazards if they enter the cellar. If implemented correctly, OSHA regulations and guidelines should provide the necessary safeguards to produce a safe working environment anywhere on the winery grounds.

Below is an example of the permit form that Gravity Wine House uses to grant access to and monitor conditions of confined spaces. Other versions of a confined space entry permit may be used while still being OSHA compliant.

Example of Entry Permit Form used at Gravity Wine House