Yes, another example of an organic chemical that is not good for the environment.
Here is the MSDS on Methyl-Bromide (CH3-Br)
Incidentally, among others I am currently reading a book on the effect of Soil Organic Matter on soils. With increased Soil Organic Carbon soils are able to Adsorb toxic chemicals and suppress their toxic effects. This chemical is very volatile and therefore able to vapourize and drift great distances but, increased organic matter in soils will still help to sequestor the toxic effects of methyl-bromide or any other toxic chemicals like DDT. Of course, the best bet is to not use the chemicals and employ organic techniques in gardening and in agriculture.
There is a myth out there that organic agriculture cannot supply the world food need. But, many studies have been done both in North America and in Europe and Africa where Organic Fertilized Wheat and other grains were grown along with chemically fertilized What and other grains and low and behold, the organically grown grains had a higher yield and had less pathogens that did that of the chemically grown plants.
Similar studies were done with herbicided and pesticides and the same results occurred.
To date, I have only encountered problems with Soil Organic Carbon (and the term Soil Organic Carbon (to me) seems a bit redundant because by definition an organic chemical is a chemical with a carbon backbone but, that's that.) and the problem is with manures being added to soils. There are actually two problems that can occur. One is that with continued manure additions to soil, the element Phosphorous (P) tends to accumulate and salt levels in soil can become toxic. Second, with continued addition of manures to soil, P and other elements (in chemical compounds) can leach out of the soil into water supplies, contaminating them.
Of course, the only real way to counteract this effec is to add more so-called Organic Carbon (OC) in the form of leaves, cover crops, wood chips and so on. In short, add browns that have a higher C:N ratio. This increase is OC allows the chelation of other elements that are essential for plant growth.
And as previously said: With increased Soil Organic Carbon (SOC) other toxic chemicals are adsorbed into the soil and chelated into non toxic forms. In fact, Magnesium (another element that is essential for plant growth (Chlorophyll is just a Mg ion chelated by carbon) combined with methyl-Bromide would combine to form CH3MgBr which would then chemically attach to some other organic compound. There goes the problem chemical. The MgBr+ would then release from the CH3 and go and work it's magic with another methyl-bromide compound.