AsureQuality, a government-owned enterprise that provides food safety and biosecurity services globally to the food and primary production sectors, also carries out inspections of dairy sheds.
"But other types of farms are not part of the AsureQuality visits, and some of those farmers are probably not as conscientious as to where and how chemicals are stored.
"On busy farms, agrichemicals are typically stacked where convenient, often not locked up, or stored away from other dangers such as fuel and fertiliser. There is a significant risk from flammable chemicals."
There is also risk associated with decanting chemicals into smaller containers for portability, says Dean. "I've seen chemicals in milk bottles, soft drink bottles and old oil containers."
Dean says the worst accidental misuse he has seen was when 150 replacement heifers were drenched with a pour-on.
"I'm sure some farmers feel it is a bit over the top to have to store chemicals in locked sheds and to keep them away from other on-farm chemicals, such as fuel and fertiliser.
They will use a pump shed, for example, because it is lockable and has electricity, but this means they are storing chemicals where they get their water from - this is quite common."
It is also common to find chemicals stored in sheds that do not have the required safety signage, and are not bunded to contain any spills.
Appropriate signage is required on any shed that is used to store agrichemicals.
This includes the Hazchem sign and No Smoking signs. Each sign tells its own story.
Hazchem 2WE, for example, tells the fire brigade to use a spray nozzle (that's the 2) or dry powder.
The W means wear breathing apparatus and the E means consider evacuating the area.
"I do get concerned that there are large volumes of chemicals and fertilisers on properties that the local fire brigades don't know about. Every farmer storing chemicals should let their local fire brigade know what they've got and where it is located on farm. This is a legal requirement."
For agrichemical storage of less than 100L, farmers should have a spill kit and an emergency response plan on the outside wall of shed. If more than 100L, and for Tracked substances stored in excess of 100L, there are different rules.
Farmers should create a manifest, list the chemicals and their coding and show the maximum quantities, even if partly used, by class. This total has to go to the nearest fire station.
"Old-school" farmers often tend to ignore the requirement for protective clothing and equipment such as goggles and masks, says Dean, but the younger generation is much more conscientious.
"One other concern I have is chemicals are often stored on-farm with easy access. Farmers should bear in mind that visitors and holidaying family members might not be as up to speed as their own children about the dangers."
Dean's concerns are shared by AsureQuality field technician Chris Johnson from Mosgiel, who personally handles a lot of on-farm audits for meat companies.
"We always stress the importance of proper storage of agrichemicals and animal health products," says Chris, "and that it is important that the two sets of products be stored apart from each other. The use of agrichemicals on farm is not as bad as it once was.
Certainly, the new generation of farmers has improved the situation over the past 10-20 years."