Health and safety is often overlooked when it comes to using spray paint however there are a few essential precautions you should take before approaching a project.
Ignoring these can result in both immediate and long term effects ranging from drowsiness to dizziness, to dermatitis and even kidney failure.
The first step is to ensure that your work area is properly ventilated. Ideally, working outside is the best way to ensure this, however if that's not an option, make sure you have adequate ventilation by using a fan or opening windows and doors when painting indoors.
A common dust mask has little to no effect on the prevention of inhaling toxic fumes, a professional respirator similar the one shown below can be picked up for less than $26 and can guarantee safety and protection, especially over long periods of time. An efficient mask should cover your nose and mouth. It should have at least two filters. The outside filter is called a "dust filter", and usually consists of a paper based filter in plastic casing. The outside filter stops you inhaling the dusty particles of paint mist. The inside filter is a "gas filter", and usually consists of a coal-based substance in a metal casing. This is the filter that stops the gas/fumes - which you may not notice as easily as the "paint dust" - yet this is the most hazardous aspect of using aerosols.
Although not an essential step, wearing protective gloves can save you time from washing paint off your hands and fingers. Spray paint is usually very viscous and can get under your nails if you aren't careful. Montana paint is especially stubborn to remove due to its highly pigmented formula.
Another important precaution you should take is wearing some form of safety goggles at all times but especially when painting indoors. Spray paint contains all kinds of harsh chemicals and prolonged exposure can sometimes lead to permanent eye issues, and in extreme cases, blindness.
An important tip to remember is the value of a large sheet or rag to help catch the excess paint particles that fly around when using a can. Spray paint has a tendency to get everywhere when being used, and 9 times out of 10 you will discover paint that has settled surprisingly far away from your project so make sure there is an old drop cloth there to collect it.
Setting your project up near waist or chest level can improve your accessibility resulting in a better finish, but more importantly, it can prevent posture and back issues that can arise from being constantly crouched over. For example, if you are painting a bike frame, use bungee cords to suspend it at a decent level.