Summer brings longer days, increased activity, and higher temperatures—but it also introduces additional hazards when working with hazardous materials. Many employees understand the dangers associated with chemicals, fuels, fertilizers, pesticides, and compressed gases, but fewer realize that these materials can behave very differently as temperatures rise.
Heat can significantly affect the physical and chemical properties of hazardous materials, increasing the risk of leaks, fires, explosions, toxic releases, and employee exposure. Understanding these changes is critical to maintaining a safe workplace during the summer months.
Heat Increases Pressure
One of the most common effects of rising temperatures is increased pressure inside containers. As liquids and gases warm, they expand. In sealed containers, this expansion can cause internal pressure to build rapidly.
This is especially important for compressed gases such as propane, anhydrous ammonia, and other pressurized products commonly found in agricultural operations. Tanks and cylinders exposed to direct sunlight may experience significantly higher internal pressures than those stored in shaded areas. While safety relief devices are designed to protect these containers, excessive pressure can cause releases of hazardous materials, creating both safety and environmental concerns.
Increased Evaporation Creates Additional Hazards
Many hazardous materials become more volatile in hot weather. As temperatures increase, liquids evaporate more quickly, producing greater concentrations of vapors.
These vapors may present several hazards:
- Increased inhalation exposure for employees.
- Greater potential for flammable atmospheres.
- Increased odor complaints from neighboring properties.
- Higher likelihood of vapor releases during transfers and handling operations.
Materials such as fuels, solvents, pesticides, and certain fertilizers can all become more hazardous when elevated temperatures increase vapor production.
Chemical Reactions Can Accelerate
Heat often acts as a catalyst that speeds up chemical reactions. Materials that are stable under normal conditions may react more quickly when exposed to excessive temperatures.
Some chemicals may:
- Decompose more rapidly.
- Lose effectiveness or product quality.
- Generate heat internally.
- Produce hazardous byproducts.
For this reason, manufacturers frequently specify maximum storage temperatures for certain products. Employees should always follow storage recommendations listed on product labels and Safety Data Sheets (SDSs).
Anhydrous Ammonia Presents Unique Summer Challenges
For agricultural retailers, anhydrous ammonia deserves special attention during hot weather. As ambient temperatures rise, the pressure inside ammonia tanks increases significantly.
Higher pressures can place additional stress on valves, hoses, fittings, and other system components. Even small leaks can release large quantities of ammonia vapor, which can cause severe burns to the skin, eyes, and respiratory system. Regular inspections become even more important to identify damaged valves, deteriorated hoses, corrosion, or other defects that could lead to a release.
Employee Exposure Risks Increase
Hot weather not only affects hazardous materials—it also affects workers.
Employees working in high temperatures may experience heat stress, fatigue, and dehydration. These conditions can reduce concentration and increase the likelihood of mistakes during hazardous material handling activities.
Simple errors such as failing to secure a valve, incorrectly connecting a hose, or overlooking a leaking fitting can have serious consequences when hazardous materials are involved.
Employers should ensure workers have access to water, rest breaks, shade, and proper training to recognize heat-related illness symptoms.
Summer Safety Best Practices
To reduce risks associated with hazardous materials during hot weather:
- Store hazardous materials according to manufacturer recommendations.
- Protect containers from excessive heat and direct sunlight whenever possible.
- Inspect tanks, cylinders, valves, hoses, and fittings regularly.
- Verify pressure relief devices are in good condition.
- Follow all SDS storage and handling requirements.
- Monitor employees for signs of heat stress.
- Conduct routine training on summer-specific hazards.
- Have emergency response procedures readily available and reviewed with employees.