Reddit mentions of Nightstick XPP-5422G 3 AA Intrinsically Safe Permissible Dual-Light Flashlight, Green

More line than you think you need. Double the line. You can never have enough line.

Waterproof, powerful flashlight my recommendation

Plastic bag with a lanyard for valuables/wallets/phones/licenses. Alternatively, a pelican case.

A pair of vice grip pliers ("The wrong tool to get every job done right")

A knife, as others said. I work professionally on the water as well as boating recreationally. The Myerchin Rigging Knife is the best all purpose knife to have on board. It might be a little overkill, but when you need a line cut fifteen seconds ago, you'll be glad you have it.

A VHF handheld radio and a knowledge of what channels are monitored by the USCG (13, 16, 22A), Commercial traffic (13/16) and local police/fire departments

Spare fuses, bulbs, plugs

A Towboat US membership

A bigger, heavier anchor if you're anywhere with a decent amount of current (rivers, oceans). I'm very much a proponent of overkill when it comes to anchoring. I use an anchor way bigger than my 20' pontoon needs, and it's a tad pricey, but once I drop it and pay out the scope, I rarely worry about dragging.

Bag of cleaning supplies. Rags, paper towels, and the holy trinity of vinyl care: melamine pads, CLR Mold & Mildew, and 303 protectant

Most important item of all: A bleach bottle with the bottom cut off

Fenix, Streamlight, Nightstick, and Pelican all make relatively inexpensive Intrinsically Safe lights - $20-40. They tend to be lower performing since they’re usually powered by Alkalines, but they’re cheap enough that you may want to keep one on hand.

I've heard good things about the Streamlight Survivor, but I've only really used corded cap lamps like Koehler wheatlamps on hardhats with a bracket, and not for structural firefighting. The Nightstick XPP-5442G also looks good, and when I had the chance to play with it, beat it up, it held up well. (http://www.amazon.com/Nightstick-XPP-5422G-Intrinsically-Permissible-Dual-Light/dp/B007RKKERA/ref=sr_1_sc_1?s=hi&ie=UTF8&qid=1426760247&sr=1-1-spell&keywords=nightsick)

Mining style cap lamps are great in that they've got a really long life, tough as fuck, they're all intrinsically safe, but they generally need a bracket, and are intended more for work. They'll fall off too easily, but they've got a cord so they won't go far...but they can also get caught on things. And the battery needs to be mounted on a belt, and they're usually rechargeable rather than able to take a fistfull of AAs. They'll cut through smoke decently if held low.

Other accessories include a halo (reflective elastic band) with a can of dip stuck in it. One of the guys on our team used a gopro in a recent training exercise underground at a mine in smoke, fire, climbing through rock and it held up really well.

If intrinsically safe torches are important at your work, I'd recommend the Pelican Nightstick

It's all we use at work, but all tooling here is work provided (military tool control rules). Hi-vis casing so it stands out if you drop it. Handy dandy wrist lanyard and belt clip. Plus it has a second LED on the underside. The main lamp is quite a bright, focused beam, while the bottom one a wider spread. I use the bottom on regularly, for example by clipping the torch to my chest so the bottom light shines outwards, or by standing the torch up and letting it shine out as a very easy to position inspection lamp.