2. The pipeline stretches right across ALASKA from Prudhoe Bay in the north Passing Fairbanks in the middle and Valdez in the south

3. The Oil is out in the Beaufort Sea and is drilled for from oil rigs. The sea is frozen for most of the year and so … … it was too dangerous for oil tankers.

4. Half of the 799-mile pipeline is buried and half rests on supports above ground, to avoid permafrost melting that can lead to structural and environmental damage. Up to two million barrels of crude oil are pumped through the four-foot diameter pipeline daily, cooling from an average temperature of 49 degrees Celsius at Prudhoe Bay to about 21 degrees Celsius at Port Valdez. Extreme cold makes pumping oil difficult

5. Arctic tundra along the Dalton Highway, Alaska Tundra vegetation is easily damaged by construction Regrowth would be very slow because the climate is so difficult

6. Pipeline crosses caribou migration route – may stop movement - may affect feeding patterns - may affect breeding patterns So scientists protect them

7. View Heading south across the Brooks Range on the way to Fairbanks The pipeline had to cross mountains up to 1460 metres high Such as the Brooks Range

8. The road crosses over the Yukon on a 1000 metre bridge. The Yukon is about 800 metres wide here. The pipeline is carried on a shelf on the side of the bridge. Several major rivers have to be crossed. Difficult and expensive technology needed.

9. Major oil spill Likely if leak goes unnoticed … inserted so sections of the pipeline can be turned off in case a leak is detected. The image shows a gate valve …

10. The TAPS crosses three mountain ranges, several basins, and an arctic coastal plain. Soil conditions vary substantially and include many permafrost areas. This required about half of the TAPS pipeline to be constructed above ground on supports rather than being buried Image shows pipeline above ground – near camera – but below ground in distance

11. The freeze-thaw action of arctic permafrost subjects buried sections of the pipeline to significant bending, and oil temperature fluctuations introduce high thermal stresses in the pipe wall. It would be costly to drill down to test buried pipes for damage The underground pipeline may thaw the permafrost Causing the foundations to collapse and then the pipeline to buckle

12. The pipeline could be a target for a terrorist attack on the USA economy. The FBI are meant to protect it.

13. The pipeline crosses an earthquake zone which could damage the pipe and lead to leaks

14. The Prudhoe Bay complex covers 250 square miles and employs thousands of workers. How could something so huge smack in the middle of the Arctic not disrupt the area's natural environment? The oil companies claim that oil activities on the North Slope have had no adverse effect on wildlife and their habitat. This is a hard pill to swallow. Pipeline milepost 0. Surface thawing and movement in summer can cause pipeline to buckle and puncture

15. Every kind of truck were hauling up the Alaska Highway in the early 70's to the Alyeska Pipeline at Prudhoe Bay. A lot of the southern 48 drivers had never seen snow or ice before. Heavy snowfall endangers buildings Causes possible collapse And limits access

16. Serious weather conditions likely, including fogs, gales, floods. Even natural hazards like tidal waves called tsunamis caused by Earthquakes

17. Loading piers at the Valdez terminal. Here, oil from the trans-Alaska pipeline is loaded onto tankers for shipment to West Coast states. At this terminal, oil was loaded onto the Exxon Valdez for shipment to Los Angeles/Long Beach. Human error can cause accidents too!